Implantable pump system having a rectangular membrane

ABSTRACT

An implantable pump system is provided, including an implantable blood pump suitable for use as a partial support assist device, the system further including an extracorporeal battery and a controller coupled to the implantable pump, and a programmer selectively periodically coupled to the controller to configure and adjust operating parameters of the implantable pump. The implantable pump includes a flexible membrane coupled to an electromagnetic actuator including a magnetic assembly and electromagnetic assembly, so that when the electromagnetic assembly is energized, the electromagnetic assembly causes wavelike undulations to propagate along the flexible membrane to propel blood through the implantable pump. The controller may be programmed by a programmer to operate at frequencies and duty cycles that mimic physiologic flow rates and pulsatility while operating in an efficient manner that avoids thrombus formation, hemolysis and/or platelet activation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/940,856, filed Mar. 29, 2018, now U.S. Pat. No. 10,933,181, whichclaims priority to U.S. Provisional Application Ser. No. 62/592,349,filed Nov. 29, 2017, U.S. Provisional Application Ser. No. 62/505,023,filed May 11, 2017, and U.S. Provisional Application Ser. No.62/480,333, filed Mar. 31, 2017, the entire contents of each of whichare incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to heart pumps and moreparticularly to implantable pumps having an approximately rectangularprofile that employ a membrane to propel blood through the pump.

BACKGROUND

The human heart is comprised of four major chambers with two ventriclesand two atria. Generally, the right-side heart receives oxygen-poorblood from the body into the right atrium and pumps it via the rightventricle to the lungs. The left-side heart receives oxygen-rich bloodfrom the lungs into the left atrium and pumps it via the left ventricleto the aorta for distribution throughout the body. Due to any of anumber of illnesses, including coronary artery disease, high bloodpressure (hypertension), valvular regurgitation and calcification,damage to the heart muscle as a result of infarction or ischemia,myocarditis, congenital heart defects, abnormal heart rhythms or variousinfectious diseases, the left ventricle may be rendered less effectiveand thus unable to adequately pump oxygenated blood throughout the body.

The Centers for Disease Control and Prevention (CDC) estimates thatabout 5.1 million people in the United States suffer from some form ofheart failure. Heart failure is generally categorized into fourdifferent stages with the most severe being end stage heart failure. Endstage heart failure may be diagnosed where a patient has heart failuresymptoms at rest in spite of medical treatment. Patients may havesystolic heart failure, characterized by decreased ejection fraction. Inpatients with systolic heart failure, the walls of the ventricle areweak and do not squeeze as forcefully as a healthy patient.Consequently, during systole a reduced volume of oxygenated blood isejected into circulation, a situation that continues in a downwardspiral until death. Patients may alternatively have diastolic heartfailure (HFpEF) wherein the heart muscle becomes stiff or thickenedmaking it difficult for the affected chamber to fill with blood. Apatient diagnosed with end stage heart failure has a one-year mortalityrate of approximately 50%.

There is a category of patients who exhibit an advanced stage of heartfailure but have not yet achieved end stage heart failure. Patients inthis category may have severely symptomatic heart failure but somepreserved end-organ function. Typically, the condition of these patientsdeteriorates rapidly over a short period of time and may ultimatelyrequire a left ventricular assist device (LVAD) and/or a hearttransplant. Presently, the only alternative to a heart transplant is amechanical implant. While in recent years mechanical implants haveimproved in design, typically such implants will prolong a patient'slife by a few years at most, and include a number of co-morbidities.

Fortunately, patients who have not yet reached end stage heart failuremay avoid or prolong a full-support LVAD and/or heart transplant byimplantation of a smaller pump. Patients in this category whosecondition does not yet warrant a conventional full-support LVAD could betreated effectively with partial-support assist devices providingpartial flow support and requiring less invasive surgery. Forcomparison, implantation of an LVAD device typically requires sternotomyand cardiopulmonary bypass.

One such partial-support assist device is the CircuLite SynergyMicro-pump device. The CircuLite Synergy Micro-pump device providespartial flow support and may serve as a bridge to LVAD implantation orheart transplantation. The CircuLite device, similar to the devicesdescribed in at least U.S. Pat. Nos. 6,116,862 and 8,512,012, has acylindrical shape similar to a AA battery and incorporates a rotary pumphaving an impeller. The pump is designed to move up to 3 liters of bloodper minute and to deliver oxygenated blood directly from the left atriumto the subclavian artery. See P. Mohite, A Sabashnikov, A. Simon, AWeymann, N. Patil, B. Unsoeld, C. Bireta and A. Popov, Does CircuLiteSynergy assist device as partial ventricular support have a place inmodern management of advanced heart failure?, Expert Rev. Med. Devices,published online 2 Dec. 2014, pages 1-12. To connect the pump to thepatient's vasculature, an ePTFE graft is positioned between the pumpoutlet and the subclavian artery to delivery oxygenated blood thereto,while an inflow cannula is surgically connected between the pump inletand the left atrium.

While the CircuLite device offers patients an alternative that providesclinical benefits, several problems with the device have beendocumented. One problem observed during clinical testing of theCircuLite device is failure due to thrombosis. Id. The CircuLite deviceemploys an impeller and has a size comparable to that of a AA battery,roughly 14 mm×49 mm. To produce an output flow of up to 3 liters ofblood per minute, the impeller—which has a diameter of roughly 14mm—must be rotated at high RPM. However, the higher the RPMs, thegreater the shear stress applied to the blood and thus the greater therisk of thrombosis.

Yet another problem with the CircuLite device is the configuration ofthe inflow cannula and the need to insert the inlet into the leftatrium. Unlike the left ventricle, which is thick and muscular, theatrial wall is relatively thin and fragile. For this reason, an inflowcannula ring cannot be used to fix the cannula to the heart chamber. Asa result, it was observed that the cannula insertion site is prone toleakage. Id. Also, with a diameter of roughly 14 mm, and a mostlycircular cross-section, the CircuLite device noticeably protrudes fromthe chest of the patient, which some patients may find unaesthetic.

Other partial-support pump devices suffer from problems similar to theCircuLite Synergy device. HeartWare produces a device similar to theCircuLite device, but which has a diameter of 20 mm. The HeartWareproduct is believed to suffer from the same shortcomings as theCircuLite device.

Other partial-support pump devices have a cylindrical shape and utilizea centrifugal pump having an impeller such as the one described in U.S.Pat. No. 6,723,039 which is assigned to CircuLite and Foundry LLC. Theimplantable pump described in the '039 patent provides partialcirculatory support much like the CircuLite Synergy device. Yet, anotherpartial-support pump device is Abiomed's Symphony device, which employsa centrifugal pump and is also implanted in the chest region.

Other types of partial-support pump devices are known that accelerateblood axially. For example, Abiomed's Impella pump, similar to the pumpdescribed in U.S. Pat. No. 7,736,296, is cylindrical in shape and pullsblood into an inlet area at one end. As described in the '296 patent,the pump involves an axial flow pump having a number of blades extendingfrom a hub that accelerate the blood, which is expelled from an opposingend. While Abiomed's Impella pump is intended to be implanted in theleft ventricle and aorta, a similar device by Procyrion, the Aortixdevice, works in a similar fashion but is an intra-aortic pump that issuspended in the aorta. U.S. Pat. Nos. 8,012,079 and 9,572,915 toProcyrion describe pumps similar to the Aortix device and discuss axialflow pumps having an impeller to propel blood from one of its ends tothe other.

While all the foregoing devices are partial-support pump devices thatmay result in clinical benefits, each of the partial-support pumpdevices share similar shortcomings with the CircuLite Synergy device.Specifically, each of these pumps have a relatively small blade orimpeller that rotates at a high rate of speed to partially support bloodcirculation. For the reasons discussed above with regard to CircuLite,these pumps too are believed to present an increased risk of thrombosiscaused by excessive shear stress and trauma to the blood cells, and riskof platelet activation. Furthermore pumps like the Abiomed's Symphonydevice generate an unpleasant noise when in use.

Accordingly, there is a need for an energy efficient implantable pumphaving light weight, small size, and a delivery mechanism for partiallysupport blood circulation with minimal blood damage.

SUMMARY OF THE INVENTION

The present invention overcomes the drawbacks of previously-knownpartial-support assist devices and methods by providing an implantablepump system having an undulating membrane capable of producing a widerange of flow rates while applying low shear forces to the blood,thereby reducing hemolysis and platelet activation relative topreviously-known systems.

In accordance with one aspect of the invention, the implantable bloodpump system includes an implantable pump, a controller and arechargeable battery, each electrically coupled to one another. Thesystem further may comprise a programmer that communicates with thecontroller to set and change pumping parameters.

The implantable blood pump may be used in a partial-support assistdevice. The implantable pump may include a housing, a rectangularmembrane disposed within the housing, a magnet assembly disposed withinthe housing including one or more magnets, and an electromagneticassembly disposed within the housing. The housing has an inlet and anoutlet and is configured to be implanted within a patient, preferably tobe in fluidic communication with the heart. The electromagnetic assemblymay generate, when electrically activated, a magnetic field applied tothe one or more magnets to induce wave-like deformation of therectangular membrane, thereby pumping blood from the inlet, along therectangular membrane, and out the outlet.

The electromagnetic assembly may include a first electromagnet portionand a second electromagnet portion. The magnet assembly may be disposedbetween the first electromagnet portion and the second electromagnetportion. The first electromagnet portion and the second electromagnetportion may be electrically activated independently. The firstelectromagnet portion and the second electromagnet portion may generatethe magnetic field having a polarity that is dependent on direction ofcurrent in each of the first electromagnet portion and the secondelectromagnet portion. The first electromagnet portion and the secondelectromagnet portion may exhibit the same polarity or differentpolarities when the current is applied in the same direction.Alternating current applied to the electromagnetic assembly may causethe magnet assembly to reciprocate thereby causing the rectangularmembrane to reciprocate to induce the wave-like deformation.

The implantable blood pump constructed in accordance with the principlesof the present invention may have a generally rectangular housing havingrounded or beveled edges and an inlet and an outlet. The implantableblood pump has a membrane assembly including a rectangular membranesuspended in the rectangular housing by a moving magnet at one end andguide posts at the other. To propel blood from the inlet to the outlet,the moving magnet is attracted to an electromagnetic assembly alsodisposed within the housing. The electromagnetic assembly may include afirst electromagnet portion and a second electromagnet portion, arrangedsuch that the first electromagnet portion is positioned above the movingmagnet and the second electromagnet portion is positioned below themoving magnet.

An electrical signal may be sent to the electromagnet portions from thecontroller and/or battery that causes the electromagnetic portions togenerate a magnetic field and thus attract the moving magnet to eitherthe first electromagnet portion or the electromagnetic portion. Themoving magnet may move toward either the first electromagnet portion orthe second electromagnet portion. The current applied to theelectromagnetic assembly may then be reversed, attracting the movingmagnet to the other electromagnetic portion. By alternating the currentapplied to the electromagnet portions, and thus causing the movingmagnet to move toward either the first or second electromagnet portions,wavelike deformations may be induced in the rectangular membrane. Whenblood is delivered to rectangular membrane the wavelike deformations maytransfer energy to the blood thereby propelling the blood along the topand bottom of rectangular membrane and ultimately out of outlet of theimplantable pump. The blood may be directed through and outlet cannulato the right subclavian artery or other artery to deliver oxygenatedblood to the rest of the body.

The electromagnetic assembly may include a first electromagnet portionand a second electromagnet portion that cause the magnet assembly toreciprocate between first electromagnet portion and the secondelectromagnet portion. The wave-like deformations in the rectangularmembrane may propagate along the rectangular membrane from an end of therectangular membrane coupled to the magnet assembly towards an opposingend of the rectangular membrane. The electromagnetic assembly maygenerate the magnetic field to pump the blood at a blood flow rate, andthe electromagnetic assembly may generate an adjusted magnetic field bymanipulating the current applied to the electromagnetic assembly toadjust the blood flow rate. The electromagnetic assembly may generatethe magnetic field to pump the blood at the blood flow rate between 1and 5 liters per minute.

The implantable pump may include a mounting structure disposed withinthe housing and secured to the housing. The magnet assembly may movewithin the housing along linear guides secured to the mountingstructure. The mounting structure may be rectangular in shape andinclude a circular inlet through a surface of the mounting structure topermit blood flow through the mounting structure.

The implantable pump may have a membrane assembly disposed within thehousing that includes a mounting structure secured to the housing and amembrane holder secured to the mounting structure at one end of themembrane holder and coupled to the rectangular membrane at an opposingend of the membrane holder. The membrane holder may include a portionconfigured to be affixed to the mounting structure and a flexibleportion configured to be coupled to the rectangular membrane. Themembrane holder may be electromagnetic and in electrical communicationwith the electromagnetic assembly. The membrane assembly may include amembrane clamp configured to couple the membrane to the membrane holder.The membrane clamp may be electromagnetic and in electricalcommunication with the electromagnetic assembly.

The implantable pump may include a funnel assembly disposed within thehousing adjacent to the outlet. The funnel assembly may have a topfunnel portion and a bottom funnel portion, the top funnel portionpositioned over at least a portion of the rectangular membrane and thebottom portion positioned below at least a portion of the rectangularmembrane. The top surface of the bottom funnel portion and the bottomsurface of the top funnel portion may provide a flow channel thatnarrows as the flow channel nears the outlet of the housing. Theimplantable pump may include first and second guide posts each having afirst end and a second end. The first and second guide posts may span adistance between the top and bottom funnel portions, the first end ofthe first and second guide posts coupled to the bottom funnel portionand the second end of the first and second guide posts coupled to thetop funnel portion such that the first and second guide posts arepositioned parallel to one another. First and second guide postreceiving portions may be included such that the first guide postreceiving portion accepts the first guide post and the second guide postreceiving portion accepts the second guide post. The first and secondguide posts may keep the rectangular membrane in tension and to guideand permit movement of an end of the rectangular membrane along thefirst and second guide posts.

The magnet assembly may include a first magnet portion positioned abovethe rectangular membrane and a second magnet portion positioned belowthe rectangular membrane. The first magnet portion may have a polaritydifferent from the second magnet portion, and the electromagneticassembly may move towards or away the first magnetic portion or secondmagnetic portion responsive to the magnetic field. Alternating currentapplied to the electromagnetic assembly may cause the electromagneticassembly and the rectangular membrane to reciprocate between the firstmagnet portion and the second magnet portion. The electromagneticassembly may generate the magnetic field to pump the blood at a bloodflow rate and the electromagnetic assembly may generate an adjustedmagnetic field by manipulating a distance over which the electromagneticassembly reciprocates between the first magnet portion and the secondmagnet portion to adjust the blood flow rate. The electromagneticassembly may generate the magnetic field to pump the blood at a bloodflow rate and the electromagnetic assembly may generate an adjustedmagnetic field by manipulating a frequency by which the electromagneticassembly reciprocates between the first magnet portion and the secondmagnet portion to adjust the blood flow rate.

The implantable blood pump further may include an inlet cannula coupledbetween the inlet and the patient's heart and an outlet cannula coupledbetween the outlet and the patient's subclavian artery.

In accordance with one aspect, a system for energizing the implantableblood pump is provided. The system may include a rechargeable batteryconfigured to energize the implantable blood pump and an extracorporealcontroller operatively coupled in electrical communication with theimplantable blood pump via a percutaneous cable. The extracorporealcontroller may include a power connector operatively coupled inelectrical communication with the rechargeable battery. The powerconnector of the extracorporeal controller may be operatively coupled inelectrical communication with the rechargeable battery directly.

The system may include an extension cable having a first end to beoperatively coupled in electrical communication with the power connectorof the extracorporeal controller, and a second end configured to beoperatively coupled in electrical communication with the rechargeablebattery. The power connector of the extracorporeal controller may beoperatively coupled in electrical communication with the rechargeablebattery remotely via the extension cable. The system also may include asecond extension cable having a first end configured to be operativelycoupled in electrical communication with the power connector of theextracorporeal controller, and a second end configured to be operativelycoupled in electrical communication with a second rechargeable battery.

The extracorporeal controller may have an internal battery configured toenergize the implantable blood pump when the rechargeable battery isdecoupled from the power connector of the extracorporeal controller. Theextracorporeal controller may include a second power connectorconfigured to be operatively coupled in electrical communication with asecond rechargeable battery. The system may include a power supplyconfigured to be operatively coupled in electrical communication withthe power connector of the extracorporeal controller when therechargeable battery is decoupled from the power connector of theextracorporeal controller.

A system for use with the implantable blood pump is also provided wherethe system includes a controller electrically coupled to theelectromagnetic assembly. The controller electrically activates theelectromagnetic assembly to cause generation of the magnetic field. Thecontroller may be implanted subcutaneously.

In accordance with one aspect, the implantable blood pump has a membraneassembly including a rectangular membrane suspended in the rectangularhousing by a membrane holder secured to the rectangular housing by amounting structure. To propel blood from the inlet to the outlet, therectangular membrane is connected to at least one electromagneticwinding which is cause to move toward the magnet assembly also disposedwithin the rectangular housing. The magnet assembly may include a firstmagnet portion and a second magnet portion, arranged such that the firstmagnet portion is positioned above a portion of the rectangular membraneand the electromagnetic winding and the second magnet portion positionedbelow a portion of the rectangular membrane and the electromagneticwinding.

An electrical signal may be sent to the electromagnetic winding from thecontroller and/or battery that causes the electromagnetic winding togenerate a magnetic field and thus move toward either the first magnetportion or the second magnet portion. The electromagnetic winding maymove toward either the first magnet portion or the second magnetportion, thereby moving the rectangular membrane connected to theelectromagnetic winding toward either the first magnet portion or thesecond magnet portion. The current applied to the electromagneticwinding may then be reversed, attracting the electromagnetic winding andthe rectangular membrane to the other magnet portion. By alternating thecurrent applied to the electromagnetic winding, the electromagnetwinding is caused to move thereby causing wavelike deformations may beinduced in the rectangular membrane. When blood is delivered torectangular membrane the wavelike deformations may transfer energy tothe blood thereby propelling the blood along the top and bottom ofrectangular membrane and ultimately out of outlet of the implantablepump. The blood may be directed through and outlet cannula to the rightsubclavian artery or other artery to deliver oxygenated blood to therest of the body.

Methods of implanting and using the implantable pump are also providedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an exemplary embodiment of the pump system of the presentinvention comprising an implantable pump, controller, battery,programmer and mobile device.

FIG. 2 depicts the surgical implantation approach for the implantablepump.

FIG. 3 depicts the endovascular implantation approach for theimplantable pump.

FIGS. 4A-C are perspective views of the implantable pump of FIGS. 1-3 .

FIGS. 5A and 5B are, respectively, a perspective view and a schematicview of the electronic components of an exemplary embodiment of thecontroller.

FIG. 6 is a plan view of an extracorporeal battery for use in the pumpsystem.

FIGS. 7A and 7B are, respectively, a perspective view and a schematicview of the electronic components of an exemplary embodiment of theprogrammer.

FIG. 8 is a perspective view of the pump assembly without the mountingstructure.

FIGS. 9A and 9B are perspective views of the pump assembly with themounting structure.

FIGS. 10A-10C are views of various rectangular membranes for use in thepump assembly.

FIG. 11 is a perspective view of the spring system.

FIG. 12 is a cut-away cross sectional view of the pump assemblyincluding funnel assembly.

FIGS. 13A and 13B are cut-away cross sectional views of the pumpassembly.

FIG. 14 is a perspective view of an alternative embodiment of theimplantable housing.

FIG. 15 is a perspective view of an alternative electromagnetic actuatorhaving a moving electromagnetic assembly.

FIG. 16 is a perspective view of an alternative electromagnetic actuatorhaving a dual coil electromagnetic actuator.

FIG. 17 is a perspective view of an alternative mechanical actuatorhaving a mechanical actuator with a cam.

FIGS. 18A-C are perspective views of an alternative implantable pump foruse in the pump system of FIGS. 1-3 .

FIGS. 19A and 19B are perspective views of the pump assembly.

FIG. 20 is an exploded view of the pump assembly.

FIGS. 21A and 21B, are, respectively, a perspective view and a plan viewof the funnel portion of the pump assembly.

FIGS. 22A and 22B are perspective views of the membrane holder of thepump assembly.

FIGS. 23A-C are views of various rectangular membranes for use in thepump assembly.

FIGS. 24A and 24B are cut-away cross sectional views of the pumpassembly.

FIGS. 25A and 25B are cut-away cross sectional views of the pumpassembly having an undulating membrane.

FIG. 26 is a perspective view of a single electromagnetic windingembodiment of the pump assembly.

FIG. 27 is a perspective view of a dual magnet electromagnetic actuator.

FIG. 28 is a perspective view of a dual coil electromagnetic actuator.

FIG. 29 is a perspective view of a mechanical actuator with a cam.

FIGS. 30A-H illustrates various configurations for coupling a battery toa controller of the present invention, and FIG. 30I illustrates acontroller coupled to a power supply.

DETAILED DESCRIPTION

The implantable pump system of the present invention is particularlywell-suited for use as a partial-support assist device and includes anundulating membrane pump particularly suitable for partial-supportcirculation in a patient having heart failure at a stage that does notwarrant implantation of a left ventricle assist device (LVAD) or hearttransplantation. The pump system may also be suitable for patientsexhibiting heart failure with reduced ejection fraction (HFrEF) who inthe later stage may benefit from an LVAD as well as patients thatexhibit heart failure with preserved ejection fraction (HFpEF) whocurrently do not benefit from LVAD. An implantable pump systemconstructed in accordance with the principles of the present inventionmay include an implantable pump, a battery and controller as well as anextracorporeal programmer. The implantable pump preferably includes ahousing having an inlet and an outlet, a flexible membrane, and anelectromagnetic actuator having electromagnetic portions and a magnetportion. When configured as a partial-support assist device, an inletcannula may be inserted into a patient's left atrium and an outletcannula may be placed in fluid communication with the patient'ssubclavian artery. By activating the electromagnetic actuator within theimplantable pump, the membrane is induced to undulate, thereby causingblood to be drawn into the pump through the inlet cannula and expelledthrough the outlet cannula into the subclavian artery. Flow rate andpulsatility may be manipulated by changing one or more of the frequency,amplitude and duty cycle of the electromagnetic actuator assembly.

The membrane pump described herein overcomes the shortcomings in theprior art by achieving desirable flow rates for partial circulatorysupport in a manner causing minimal blood damage, thereby avoiding theproblems with thrombus formation that plagued earlier partial-supportassist devices. The implantable pump described herein is an improvementover U.S. Pat. Nos. 6,361,284, 6,658,740, 7,323,961 and 9,080,564 toDrevet, the entire disclosures of each of which are incorporated hereinby reference, which generally disclose vibrating membrane fluidcirculators. More specifically, these patents disclose a deformablemembrane disposed within a structure having an admission orifice and adelivery orifice. At the admission end, the membrane is attached to amember that provides an excitation force to the membrane, causing wavesin the membrane to travel toward the delivery orifice, therebytransferring energy to fluid within the structure and ultimatelydirecting the fluid out of the delivery orifice. The present inventionincorporates the teachings of these patents into the implantable pumpsystem described herein for use as a partial-support assist device.

Referring now to FIG. 1 , pump system 1 constructed in accordance withthe principles of the present invention is described. System 1illustratively includes implantable pump 2, controller 3, battery 4,programmer 5 and optionally, a software module programmed to run onmobile device 6. Implantable pump 2 is configured to be implanted withinthe patient and may be positioned into a subcutaneous or intra-muscularpocket inferior to the subclavian artery and in front of the rightpectoralis major muscle. Implantable pump 2 may be connected to inletcannula 7 and outlet cannula 8. Inlet cannula 7 may connect implantablepump 2 to a first heart chamber or body lumen, e.g., the left atrium LAof heart H, and outlet cannula 8 may connect implantable pump to asecond heart chamber or body lumen, e.g., the right subclavian arterySA. Outlet cannula 8, may be any kind of graft suitable for fluidcommunication between implantable pump 2 and subclavian artery SA. Forexample, outlet cannula 8 may be a ePTFE graft or other syntheticmaterial.

Controller 3 and battery 4 may be extracorporeal and sized so as to beplaced on a belt or garment worn by the patient, as illustrated in FIG.1 . Battery 4 may be electrically coupled to controller 3 via a cablethat is integrated into the belt. Controller 3 and battery 4 may be twoseparate units or may be incorporated into the same unit. Wherecontroller 3 and battery 4 are extracorporeal, cable 9 may be tunneledfrom the subcutaneous pocket to the right upper quadrant of the abdomenat which point cable 9 may exit the body. Accordingly, cable 9 mayextend from the pump in the subcutaneous pocket, through the body of thepatient to the abdomen and out the abdomen and to the extracorporealcontroller 3 and/or battery 4 on the exterior of the body. In thismanner, both controller 3 and battery 4 may be electrically coupled viacable 9 to implantable pump 2.

In an alternative embodiment, controller 3 and/or battery 4 may beenclosed within a biocompatible housing and sized to be implantedsubcutaneously in the patient's abdomen or in any other suitablesubcutaneous location. In this alternative embodiment, controller 3and/or battery 4 may include a wireless transceiver for bi-directionalcommunications with an extracorporeal programming device and/or chargingdevice. Where battery 4 is implanted subcutaneously, a secondextracorporeal battery may be worn by the patient near implanted battery4 which may charge battery 4 transcutaneously. As will be understood,the foregoing alternative embodiment avoids the use of percutaneouscable 9, and thus eliminates a frequent source of infection.

Battery 4 preferably comprises a rechargeable battery capable ofpowering implantable pump 2 and controller 3 for a period of severalhours or even days before needing to be recharged. Battery 4 may includea separate charging circuit, not shown, as is conventional forrechargeable batteries. Battery 4 preferably is disposed within ahousing suitable for carrying on a belt or holster, so as not tointerfere with the patient's daily activities. However, as explainedabove, battery may be implanted and thus battery may be disposed withina biocompatible housing.

Programmer 5 is programmed to execute programmed software routines on acomputer (e.g., laptop computer, desktop computer, smartphone, tablet,smartwatch, etc.) for use by a clinician or medical professional, forconfiguring and providing operational parameters to controller 3. Theconfiguration and operational parameter data is stored in a memoryassociated with controller 3 and used by the controller to controloperation of implantable pump 2. As described in further detail below,controller 3 directs implantable pump 2 to operate at specificparameters determined by programmer 5. Programmer 5 may be coupled tocontroller 3 via cable 10. Using programmer 5, operational parameters ofimplantable pump 2 are set and periodically adjusted, e.g., when thepatient visits the clinician.

In accordance with another aspect of the invention, mobile device 6,which may be a conventional laptop, smartphone, tablet, or smartwatch,may include an application program for bi-directionally and wirelesslycommunicating with controller 3, e.g., via WiFi or Bluetoothcommunications. Preferably, mobile device 6 is used by the patient orthe patient's caretaker. The application program on mobile device 6 maybe programmed to permit the patient to send instructions to controller 3to modify or adjust a limited number of operational parameters ofimplantable pump 2 stored in controller 3. Alternatively or in addition,mobile device 6 may be programmed to receive from controller 3 and todisplay on screen 11 of mobile device 6, data relating to operation ofimplantable pump 2 or alert or status messages generated by controller3.

Referring now to FIG. 2 , implantable pump 2 may be implanted using asurgical approach as is illustrated in FIG. 2 . The surgical approachinvolves creating a subcutaneous pocket, e.g., at a position inferior tothe subclavian artery and in front of the right pectoralis major muscle,in which implantable pump 2 is positioned. An incision is made in theright subclavian artery SA into which an end of outflow cannula 8 ispositioned. Outflow cannula 8 may be anastomosed to the right subclavianartery SA. The opposing end of outflow cannula 8 is inserted into thesubcutaneous pocket and coupled with implantable pump 2. To reach theheart, a mini-thoracotomy may be performed and pericardium is opened toinsert an end of inflow cannula 7 into left atrium LA. Inflow cannula 7may be secured to the left atrium using sutures. The opposing end ofinflow cannula 7 may be tunneled through intercostal space andultimately into the subcutaneous pocket to be coupled with implantablepump 2.

Alternatively, implantable pump 2 may be implanted using an endovascularapproach, illustrated in FIG. 3 . Like in the surgical approach, theendovascular approach involves creating a subcutaneous pocket, e.g., ata position inferior to the subclavian artery and in front of the rightpectoralis major muscle, in which implantable pump 2 is positioned. Theendovascular approach also involves an incision made in the rightsubclavian artery SA into which an end of outflow cannula 8 ispositioned and anastomosed to the right subclavian artery SA. Theopposing end of outflow cannula 8 may similarly be inserted into thesubcutaneous pocket and coupled with implantable pump 2. However, unlikethe surgical approach described above, to reach the right atrium, inflowcannula 7 is inserted through the right subclavian vein. In thisapproach, an incision is made in the right subclavian vein SV and aguidewire is inserted and advanced through the superior vena cava SVC toright atrium RA. Upon reaching right atrium RA, a transseptal puncturetechnique may be used to advance the guidewire into left atrium LA.Inflow cannula 7 may then be advanced to left atrium LA over theguidewire and may be anchored to the atrial septum.

Referring now to FIG. 4A-4C, implantable pump 2 is illustrated ingreater detail. Implantable pump 2 includes pump housing 12 which ismade of a biocompatible material, such as titanium, and is sized to beimplanted within a patient's chest as described above. Pump housing 12may have a general rectangular shape or may narrow at one or both endsand may be two or more pieces that fit together by, for example, threadsor welding, to form fluid tight pump housing 12. Pump housing 12 mayhave any size suitable for pump assembly 16 to be disposed within pumphousing 12. Pump housing includes inlet 13 and outlet 14 through whichblood may flow in and out, respectively. Pump housing 12 in FIG. 4Cdemonstrates a narrowing step-down feature to facilitate blood flowtowards outlet 14. Pump also may include electrical port 15 to attachimplantable pump 2 to cable 9. Electrical port 15 may permit cable 9 totransverse pump housing 12 and connect to pump assembly 16 in a fluidtight manner. Cable 9 may deliver electrical wires from controller 3 andbattery 4 to pump assembly 16.

With respect to FIGS. 5A and 5B, controller 3 is illustrated in greaterdetail. As depicted in FIG. 1 , controller 3 may be sized and configuredto be worn on the exterior of the patient's body or may be sized andconfigured to be implanted subcutaneously. Controller 3 includes inputport 17, output port 18, battery port 19, indicator lights 20, display21, status lights 22 and buttons 23. Input port 17 is configured toperiodically and removably accept cable 10 to establish an electricalconnection between programmer 5 and controller 3, e.g., via a USBconnection. In this manner, a clinician may couple to controller 3 toset or adjust operational parameters stored in controller 3 forcontrolling operation of implantable pump 2. In addition, whenprogrammer 5 is coupled to controller 3, the clinician also may downloadfrom controller 3 data relating to operation of the implantable pump,such as actuation statistics, for processing and display on display 38of programmer 5. Alternatively, or in addition, controller 3 may includea wireless transceiver for wirelessly communicating such informationwith programmer 5. In this alternative embodiment, wirelesscommunications between controller 3 and programmer 5 may be encryptedwith an encryption key associated with a unique identification number ofthe controller, such as a serial number.

Battery port 19 is configured to removably accept a cable connected tobattery 4 which may be incorporated into the belt illustrated in FIG. 1. Battery 4 may be removed from the belt and disconnected fromcontroller 3 to enable the patient to periodically replace the batterywith a fully charged battery. It is expected that the patient will haveavailable to him or her at least two batteries, so that while onebattery is coupled to controller 3 to energize the controller andimplantable pump 2, the other battery may be connected to a rechargingstation. Alternatively, or in addition, battery port 19 may beconfigured to accept a cable that is coupled directly to a power supply,such as a substantially larger battery/charger combination that permitsthe patient to remove battery 4 while lying supine in a bed, e.g., tosleep.

Output port 18 is electrically coupled to cable 9, which is coupled toimplantable pump 2 through electrical port 15 of pump housing 12. Cable9 provides energy to energize implantable pump 2 in accordance with theconfiguration settings and operational parameters stored in controller3. Cable 9 also may permit controller 3 to receive data from sensorsdisposed in implantable pump 2. In one embodiment, cable 9 is designedto extend percutaneously and may be an electrical cable having abiocompatible coating. Cable 9 may be impregnated with pharmaceuticalsto reduce the risk of infection, the transmission of potentiallyhazardous substances or to promote healing where it extends through thepatient's skin.

As mentioned above, controller 3 may include indicator lights 20,display 21, status lights 22 and buttons 23. Indicator lights 20 mayvisually display information relevant to operation of the system, suchas the remaining life of battery 4. Display 21 may be a digital liquidcrystal display that displays real time pump performance data,physiological data of the patient, such as heart rate, and/oroperational parameters of the implantable pump, such as the target pumppressure or flow rate, etc. When it is determined that certain parameterconditions exceed preprogrammed thresholds, an alarm may be sounded andan alert may be displayed on display 21. Status lights 22 may compriselight emitting diodes (LEDs) that are turned on or off to indicatewhether certain functionality of the controller or implantable pump isactive. Buttons 23 may be used to wake up display 21, to set or quietalarms, etc.

With respect to FIG. 5B, the components of the illustrative embodimentof controller 3 of FIG. 5A are described. In addition to the componentsof controller 3 described in connection with FIG. 5A, controller 3further includes microprocessor 25, memory 26, battery 27, optionaltransceiver 28 and amplifier circuitry 29. Microprocessor 25 may be ageneral purpose microprocessor, for which programming to controloperation of implantable pump 2 is stored in memory 26. Memory 26 alsomay store configuration settings and operational parameters forimplantable pump 2. Battery 27 supplies power to controller 3 to providecontinuity of operation when battery 4 is periodically swapped out.Optional transceiver 28 facilitates wireless communication withprogrammer 5 and/or mobile device 6 via any of a number of well-knowncommunications standards, including BLUETOOTH™, ZigBee, and/or any IEEE802.11 wireless standard such as Wi-Fi or Wi-Fi Direct. Controller 3 mayfurther include amplifier circuitry 29 for amplifying electrical signalstransferred between controller 3 and implantable pump 2.

Referring now to FIG. 6 , battery 4 is described. Battery 4 providespower to implantable pump 2 and also may provide power to controller 3.As described above, battery 4 may be implanted subcutaneously or may beextracorporeal. Battery 4 may consist of a single battery or a pluralityof batteries disposed within a housing, and when configured forextracorporeal use, is sized and configured to be worn on the exteriorof the patient's body, such as on a belt. Alternatively, where battery 4is implanted into a patient, battery 4 may be disposed in abiocompatible housing. Battery life indicator 31 may be provided on theexterior of battery 4 to indicate the remaining charge of the battery.Controller may be connected to battery 4 via a cable connecting batteryport 19 of controller 3 to output port 32 of battery 4. In oneembodiment, battery 4 may be rechargeable using a separate chargingstation, as is known in the art of rechargeable batteries.Alternatively, or in addition, battery 4 may include port 33 which maybe removably coupled to a transformer and cable to permit the battery tobe recharged using a conventional residential power outlet, e.g.,120/240V, 50/60 Hz AC power.

Referring now to FIGS. 7A-7B, programmer 5 is described. Programmer 5may be a conventional laptop, desktop, tablet, smartphone, smartwatchloaded with programmed software routines 34 for configuring controller 3and setting operational parameters that controller 3 uses to controloperation of implantable pump 2. As discussed above, programmer 5typically is located in a clinician's office or hospital, and is coupledto controller 3 via cable 10 or wirelessly to initially set upcontroller 3, and then periodically adjust controller 3 thereafter asrequired to adjust the operational parameters as may be needed. Theoperational parameters of controller 3 set using the programmed routinesof programmer 5 may include but are not limited to applied voltage, pumpfrequency, pump amplitude, target flow rate, pulsatility, etc. Whenfirst implanted, the surgeon or clinician may use programmer 5 tocommunicate initial operating parameters to controller 3. Followingimplantation, the patient periodically may return to the clinician'soffice for adjustments to the operational parameters which may again bemade using programmer 5.

Programmer 5 may be any type of conventional personal computer devicehaving touch screen capability. As illustrated in FIG. 7B, programmer 5preferably includes processor 35, memory 36, input/output device 37,display 38, battery 39 and communication unit 40. Memory 36 may be anon-transitory computer readable medium that stores the operating systemfor the programmer, as well as the programmed routines needed tocommunicate with controller 3. When executed by processor 35,instructions from the programmed routines stored on the non-transitorycomputer readable medium cause execution of the functionality describedherein. Communication unit 40 may include any of a number of well-knowncommunication protocols, such as BLUETOOTH™, ZigBee, and/or any IEEE802.11 wireless standard such as Wi-Fi or Wi-Fi Direct. As illustratedin FIG. 7A, the programmed routines used to program and communicate withcontroller 3 also may provide data for display on the screen ofprogrammer 5 identifying operational parameters with which controller 3controls implantable pump 2. The programmed routines also may enableprogrammer 5 to download from controller 3 operational data orphysiologic data communicated by the implantable pump and to displaythat information in real time while the programmer is coupled to thecontroller via a wired or wireless connection. The transferred data maythen be processed and displayed on the screen of programmer 5.

Referring now to FIG. 8 , pump assembly 16 is illustrated. Pump assembly16 illustratively includes membrane assembly 49, magnet assembly 41,electromagnetic assembly 42, mounting structure 44 (not shown), linearguides 45 which may optionally include spring system 60. Linear guides45 may permit magnet assembly 41 to move up and down linearly alonglinear guides 45. Spring system 60, discussed in greater detail belowwith reference to FIG. 11 , may be configured to apply a spring forcetoward a neutral center position as magnet assembly 41 deviates from thenatural position.

Referring now to FIGS. 9A and 9B, pump assembly 16 is illustratedshowing mounting structure 44. Pump assembly 16 is sized and configuredto fit within pump housing 12. Mounting structure 44, may be mounted topump housing 12 using any well-known fixation technique. For example,mounting structure 44 may include threaded grooves that correspond tothreaded grooves in pump housing 12 and may be coupled to pump housing12 using plurality of screws. Alternatively, mounting structure 44 maybe welded to pump housing 12.

Mounting structure 44 is sized and configured to be disposed within pumphousing 12 adjacent to inlet 13. Mounting structure 44 may have arectangular shape with a square cross-section. Mounting structure 44 mayhave inlet channel 71 which permits blood received at inlet 13 to flowthrough mounting structure 44. Mounting structure 44 may include inflowseparator 52 which may permit blood that enters through inlet channel 71to separate into upper flow channel 72 and lower flow channel 73.

Electromagnet assembly 42 and linear guides 45 may be coupled to orotherwise incorporated into mounting structure 44. Electromagnetassembly 42 may include first electromagnet 57 and second electromagnet58 each having an electromagnetic winding that exhibits electromagneticproperties when an electrical current is applied. First electromagnet 57may be coupled to upper flange portion 53 of mounting structure 44 as isillustrated in FIGS. 9A and 9B. Second electromagnet 58 may similarly becoupled to lower flange portion 54. In this configuration firstelectromagnet 57 may be positioned directly above second electromagnet58 and a gap may exist between first electromagnet 57 and secondelectromagnet 58.

Linear guides 45 may be coupled at one end to upper flange portion 53and another end to lower flanged portion 54 and may span the gap betweenfirst electromagnet 57 and second electromagnet 58. Linear guides 45 maybe arranged parallel to one another and perpendicular to the directionof blood flow through inlet channel 71.

Magnet assembly 41 may include upper magnet 51 which is configured tomove linearly along linear guides 45. Magnet 51 may be a permanentmagnet and may either be a single magnet or may be may include multiplemagnets coupled together to form magnet 51. Magnet 51 may be rectangularin shape and may have linear guide receiving portions that extendthrough magnet 51 through which linear guides 45 may be inserted andextend through. In this manner, magnet 51 may move up towards firstelectromagnet 57 and down towards second electromagnet 58.

Membrane assembly 49 may include membrane connector 47 and rectangularmembrane 48. As discussed in greater detail below, rectangular membrane48, may be generally rectangular in shape and may be connected to magnet51 at by membrane connector 47. Magnet 51 may include a threadedreceiving portion through which membrane connector 47 in the form ofscrews may be used to couple an end of rectangular membrane 48 to magnet51.

Alternatively, membrane connector 47 may be a clamping device thatclamps membrane 48 to magnet 51. It is understood that membraneconnector 47 may be any well-known mechanism or techniques, e.g. epoxy,screws, etc.

Membrane 48, coupled to magnet 51, as is illustrated in FIGS. 9A and 9B,may move up and down with magnet 51. Spring system 60 may optionally becoupled to linear guides 45 as illustrated in FIG. 11 . Spring systemmay be designed to position magnet 51 in a neutral position. Forexample, the neutral position may be the same plane as inflow separator52. As such, though magnet 51 may travel up and down along linear guides45, magnet 51 may be designed to return to the neutral position.

First electromagnet 57 and second electromagnet 58 of electromagneticassembly 42 may include one or more smaller metallic wires that may bewound into a coil, and may be in electrical communication with batteryand/or controller via cable 9 connected via electrical port 15. Firstelectromagnet 57 and second electromagnet 58 may be in electricalcommunication with one another and/or may be configured to operateindependently and have separate wired connections to controller 3 and/orbattery 4 via cable 9. Current flow applied to first electromagnet 57and second electromagnet 58 could be reversed depending on the operatingparameters applied. The wires of first electromagnet 57 and secondelectromagnet 58 may be insulated to prevent shorting to adjacentconductive material.

Implantable pump housing 12 may be comprised of titanium, stainlesssteel or any other rigid biocompatible material suitable for mountingpump assembly 16 to pump housing 12. Magnet assembly 41 may be comprisedof one or more materials exhibiting magnetic properties such as iron,nickel, cobalt or various alloys. Where multiple magnets make up magnetassembly 41, the magnets may be linked by metallic parts made of a highsaturation alloy, such as Vacoflux. Mounting structure too may be madefrom Vacoflux. The one or more smaller metallic wires wound into a coilin electromagnetic assembly 42 may be made of copper or any other metalhaving appropriate electromagnetic properties.

Referring now to FIGS. 10A-10C, various rectangular membranes areillustrated in greater detail. Rectangular membrane 48 may take ageneral thin rectangular shape. In a preferred embodiment, rectangularmembrane 48 has a thin, planar shape and is made of an elastomer havingelastic properties and good durability. For example, rectangularmembrane 48 may be flexible through the entire length and cross-sectionof rectangular membrane 48 such that actuation of the implantable pumpmoves rectangular membrane to create wave-like deformation that pumpsblood through the pump. Rectangular membrane 48 may have a uniformthickness from one end to the other. As yet a further alternative,rectangular membrane 48 may vary in thickness and exhibit more complexgeometries, as described further herein. For example, rectangularmembrane 48 may have a reduced thickness as the membrane extends fromone end to the other and/or may have right-angled or beveled or roundedcorners. Alternatively, or in addition to, rectangular membrane 48 mayincorporate metallic elements such as a spring to enhance the springforce of the membrane in a direction normal to plane of the membrane. Inyet another embodiment, rectangular membrane 48 may be pre-formed withan undulating shape.

FIGS. 10A-10C illustrate various rectangular membranes that may be usedin the implantable pumps described herein. As shown, each of therectangular membranes have protrusions extending from the distal end ofthe rectangular membrane in a direction orthogonal to the blood flowpath. As is illustrated in FIG. 10A, rectangular membrane 48′ has twopost receiving portions 67 and 68. Post receiving portions 67 and 68 mayhave a diameter slightly larger than that of posts 55 which may beparallel to linear guides 45 and extend from a top side of pump housing12 to a bottom side as shown in FIGS. 13A-B. Alternatively, posts 55 mayextend between upper funnel portion 64 and lower funnel portion 56 as isillustrated in FIG. 12 . Also, as shown in FIG. 10A, rectangularmembrane 48′ has extended portions 69 and 70 that each protrude from themain body of rectangular membrane 48 in a direction parallel to theblood flow path to create a space between extended portions 69 and 70.Extended portions 69 and 70 have post receiving portions 67 and 68,respectively, therein and may permit fluid to more freely escape out ofoutlet 14 of implantable pump 2. Alternatively, in FIG. 10B, the mainbody of rectangular membrane 48″ extends the entire length of themembrane without any extended portions. In FIG. 10B, the main body ofrectangular membrane 48″ has two post receiving portions 67′ and 68′. Inyet another alternative, as shown in FIG. 10C, rectangular membrane 48′″does not include the post receiving portions. This may permit the distalend of rectangular membrane 48′″ nearest outlet 14 to move more freely.

Referring now to FIG. 11 , one embodiment of spring system 60 isillustrated in greater detail. Spring system 60 may optionally becoupled or otherwise incorporated into linear guides 45. As mentionedabove, spring system 60 may provide a spring force to magnet 51 whenmagnet 51 deviates from a neutral position. As illustrated in FIG. 11the neutral position may be equidistant between upper flange portion 53and lower flange portion 54. However, spring system 60 may be designedto set the neutral position at any position between upper flange portion53 and lower flange portion 54. Spring system 60 may include upperspring portion 65 and lower spring portion 66. Upper spring portion 65and lower spring portion 66 may collectively apply a spring forceproviding increased resistance as magnet 51 deviates from the neutralposition.

Referring now to FIG. 12 , funnel assembly 50 is illustrated. Funnelassembly 50 may optionally be disposed within pump housing 12 nearoutlet 14, as is illustrated in FIG. 12 , to further narrow the bloodflow through implantable pump 2 as blood travels from inlet 13 to outlet14. Funnel assembly 50 may include upper funnel portion 64 and a lowerfunnel portion 56. As is illustrated in FIG. 12 , the thickness of thefunnel generally increases towards outlet 14. Additionally, the width ofthe flow channel may narrow as it moves inward toward outlet 14. Upperfunnel portion 64 and lower funnel portion 56 may include threadedportions that extend the through upper funnel portion 64 and lowerfunnel portion 56 or at least partway through to permit the funnelportions to be secured to pump housing 12.

Referring now to FIGS. 13A and 13B, sectional views of implantable pump2 are illustrated. In FIG. 13A, rectangular membrane 48 is seensuspended in tension between linear guides 45 and posts 55. In thisconfiguration membrane 48 is suspended within pump housing 12. Asexplained above, blood may enter pump housing at inlet 13 and travelthrough mounting structure 44 via inlet channel 71. After travelingthrough inlet channel 71, blood must travel around inflow separator 52.Inflow separator 52 separates blood flow into upper flow channel 72 andlower flow channel 73. Upper flow channel 72 is defined by a top surfaceof magnet 51 and membrane 48, on one side, and an interior surface ofpump housing 12 on the other side. Lower flow channel 73 is defined by abottom surface of magnet 51 and membrane 48, on one side, and aninterior surface of pump housing 12 on the other side. Upper flowchannel 72 and lower flow channel 73 merge at outlet 14. In this manner,after exiting inlet channel 71, and traveling around inflow separator52, blood travels along the top and bottom surface of membrane 48 untilit reaches outlet 14.

Implantable pump may be activated to pump blood from inlet 13 to outlet14 by moving magnet 51 up and down along linear guides 45. In thismanner magnet 51 may move up towards first electromagnet 57 or downtowards second electromagnet 58. To move magnet 51 up, current may beapplied to first electromagnet 57 such that first electromagnet 57generates a magnetic field that attracts magnet 51 and thus causesmagnet 51 to move toward first electromagnet 57. At the same time,second electromagnet 58 may be induced with a current that causes secondelectromagnet 58 to generate a magnetic field having the oppositepolarity of first electromagnet 57, thereby repelling magnet 51 fromsecond electromagnet 58 while first electromagnet 57 attracts magnet 51.In this manner, first electromagnet 57 and second electromagnet 58 maywork together to move magnet 51. Alternatively, second electromagnet 58may not be energized while first electromagnet 57 is energized.

To move magnet 51 down, current may be applied to second electromagnet58 such that second electromagnet 58 generates a magnetic field thatattracts magnet 51 and thus causes magnet 51 to move toward secondelectromagnet 58. At the same time, first electromagnet 57 may beinduced with a current that causes first electromagnet 57 to generate amagnetic field having the opposite polarity of second electromagnet 58,thereby repelling magnet 51 from first electromagnet 57 while secondelectromagnet 58 attracts magnet 51. Alternatively, first electromagnet57 may not be energized while second electromagnet 58 is energized.

First electromagnet 57 and second electromagnet 58 may be designed togenerate opposite polarities when current is applied in the samedirection through first electromagnet 57 and second electromagnet 58. Inthis manner, the same electrical current may be applied simultaneouslyto first electromagnet 57 and second electromagnet 58 to achieve thedesired effects. Alternatively, first electromagnet 57 and secondelectromagnet 58 may be designed to generate the same polarity whencurrent is applied in the same direction. In this configuration the samecurrent would not be applied simultaneously to first electromagnet 57and second electromagnet 58.

As spring system 60 exhibits a spring force when magnet 51 deviates fromthe neutral position, when first electromagnet 57 and/or secondelectromagnet 58 cause magnet 51 to move up toward first electromagnet57, spring system 60 may exert a downward spring force on magnet 51toward the neutral position. Similarly, when first electromagnet 57and/or second electromagnet 58 cause magnet 51 to move downward towardsecond electromagnet 58, spring system 60 may exert an upward springforce on magnet 51 toward the neutral position. The further magnet 51deviates from the neutral position, the greater the spring force appliedto magnet 51.

By manipulating the timing and intensity of the electrical signalsapplied to electromagnetic assembly 42, the frequency at which magnet 51moves up and down may be altered. For example, by alternating thecurrent induced in the electromagnetic assembly 42 more frequently,magnet 51 may be caused to cycle up and down more times in a givenperiod. By increasing the voltage applied to electromagnetic assembly42, magnet 51 may travel at a faster rate and caused to travel longerdistances from the neutral position.

As magnet 51 is coupled to rectangular membrane 48 via membraneconnector 47, movement of magnet 51 is applied to the end of rectangularmembrane 48. FIG. 13B illustrates movement by magnet 51 being applied torectangular membrane 48. As is shown in FIG. 13B, a current has beeninduced in first electromagnet 57 and/or second electromagnet 58 suchthat magnet 51 is attracted towards first electromagnet 57. The movementof magnet 51 has caused the end of membrane 48 coupled to magnet 51 toalso move up and down thereby causing wave-like deformations in membrane48. By inducing alternating current to first electromagnet 57 and secondelectromagnet 58, membrane 48 may be undulated between upper flowchannel 72 and lower flow channel 73 to induce wavelike formations inrectangular membrane 48 that moves from the edge of rectangular membrane48 coupled to magnet 51 towards outlet 14.

As rectangular membrane 48 is attached directly to magnet 51, whenmagnet 51 travels a certain distance upward or downward, the end ofrectangular membrane 48 attached to magnet 51 also travels the samedistance. For example, when magnet 51 travels 3 mm above the neutralposition, the end of rectangular membrane 48 attached to magnet 51 alsotravels 3 mm in the same direction. Similarly, the frequency at whichmagnet 51 reciprocates up and down is the same frequency at which theend of rectangular membrane 48 that is coupled to magnet 51 travels thesame distance. Preferably, the frequency is between 0 to 150 Hz, thoughother frequencies may be achieved using the system described herein.

Accordingly, when blood is delivered to inlet channel 71 and aroundinflow separator 52, it is propelled along both the top and bottom ofrectangular membrane 48 and ultimately out of outlet 14. The wavesformed in the undulating rectangular membrane may be manipulated bychanging the speed at which magnet 51 moves up and down as well as thedistance magnet 51 moves up and down. The transfer of energy from themembrane to the blood is directed along the length of membrane 48towards outlet 14, and propels the blood along both sides of rectangularmembrane 48.

In FIG. 13B magnet 51 is moving upward. As magnet 51 moves upwards, theentrance into lower flow channel 73 between a bottom surface of magnet51 and mounting structure 44 begins to increase in size while theentrance to upper flow channel 72 between an upper surface of magnet 51and mounting structure 44 begins to simultaneously decrease in size,causing blood to fill lower flow channel 73 nearest magnet 51. As magnet51 is subsequently moved downward towards second electromagnet 58, lowerflow channel 73 begins to narrow near magnet 51 and continues to narrowas a wave-like deformations in membrane 48 are propagated toward outlet14. As the wave propagates across rectangular membrane 48, blood in thelower flow channel 73 is propelled towards outlet 14. Simultaneously, asmagnet 51 moves down, the entrance to upper flow channel 72 begins toenlarge, allowing blood from inlet channel 71 to flow into this region.Subsequently, when magnet 51 is again thrust upwards, upper flow channel72 begins to narrow near magnet 51, causing wave-like deformations topropagate across membrane 48, propelling blood towards outlet 14.Preferably, the speed of the wave propagation is 1 to 1.5 m/s, thoughother propagation speeds may be achieved using the system describedherein.

By manipulating the waves formed in the undulating membrane by changingthe frequency and amplitude at which magnet 51 moves up and down, thepressure gradient within upper flow channel 72 and lower flow channel 73and ultimately the flow rate of the blood moving through implantablepump 2 may be adjusted. Appropriately controlling magnet 51 permitsoxygen-rich blood to be effectively and safely pumped from the leftatrium to the right subclavian artery and throughout the body as needed.While the pump described herein is described as pumping blood from theleft atrium to the right subclavian artery, implantable pump 2 describedherein could be used to pump blood from and to different areas, e.g.from the left ventricle to the aorta.

In addition to merely pumping blood from the left atrium to thesubclavian artery, implantable pump 2 of the present invention may beoperated to closely mimic physiologic pulsatility, without loss of pumpefficiency. Pulsatility may be achieved nearly instantaneously bychanging the frequency and amplitude at which magnet 51 moves, to createa desired flow output, or by ceasing movement of the magnet assembly 41for a period time to create a period of low or no flow output. Unliketypical rotary pumps, which require a certain period of time to attain aset number of rotations per minute to achieve a desired fluiddisplacement and pulsatility, implantable pump 2 may achieve a desiredflow output nearly instantaneously and similarly may cease output nearlyinstantaneously due to the very low inertia generated by the smallmoving mass of the moving components of the pump assembly. The abilityto start and stop on-demand permits rapid changes in pressure and flow.Along with the frequency and amplitude, the duty cycle, defined by thepercentage of time rectangular membrane 48 is excited over a set periodof time, may be adjusted to achieve a desired flow output andpulsatility, without loss of pump efficiency. Even holding frequency andamplitude constant, flow rate may be altered by manipulating the dutycycle between 0 and 100%.

In accordance with another aspect of the invention, controller 3 may beprogrammed by programmer 5 to operate at selected frequencies,amplitudes and duty cycles to achieve a wide range of physiologic flowrates and with physiologic pulsatilities. For example, programmer 5 maydirect controller 3 to operate implantable pump 2 at a given frequency,amplitude and/or duty cycle during a period of time when a patient istypically sleeping and may direct controller 3 to operate implantablepump 2 at a different frequency, amplitude and or duty cycle during timeperiods when the patient is typically awake. Controller 3 or implantablepump 2 also may include an accelerometer or position indicator todetermine whether the patient is supine or ambulatory, the output ofwhich may be used to move from one set of pump operating parameters toanother. When the patient experiences certain discomfort or a physiciandetermines that the parameters are not optimized, physician may alterone or more of at least frequency, amplitude and duty cycle to achievethe desired functionality. Alternatively, controller 3 or mobile device6 may be configured to alter one or more of frequency, amplitude andduty cycle to suit the patient's needs.

Implantable pump 2 further may comprise one or more additional sensorsfor adjusting flow output and pulsatility according to the demand of thepatient. Sensors may be incorporated into implantable pump 2 oralternatively or in addition to may be implanted elsewhere in or on thepatient. The sensors preferably are in electrical communication withcontroller 3, and may monitor operational parameters that measure theperformance of implantable pump 2 or physiological sensors that measurephysiological parameters of the patients such as heart rate or bloodpressure. By using one or more physiological sensors, pulsatile flow maybe synchronized with a cardiac cycle of the patient by monitoring bloodpressure or muscle contractions, for example, and synchronizing the dutycycle according to the sensed output.

Controller 3 may compare physiological sensor measurements to currentimplantable pump output. If it is determined by analyzing sensormeasurements that demand exceeds current output, frequency, amplitudeand/or duty cycle may be automatically adjusted to meet current demand.Similarly, the controller may determine that current output exceedsdemand and thus alter output by changing frequency, amplitude and/orduty cycle. Alternatively, or in addition to, when it is determined thatdemand exceeds current output, an alarm may sound from controller 3.Similarly, operational measurements from operational sensors may becompared against predetermined thresholds and where measurements exceedpredetermined thresholds or a malfunction is detected, an alarm maysound from controller 3.

Implantable pump 2 is sized and shaped to produce physiological flowrates, pressure gradients and pulsatility at an operating point at whichmaximum efficiency is achieved. Preferably, implantable pump 2 is sizedand shaped to achieve flow rates ranging from 1 to 5 liters per minuteat pressure gradients lower than a threshold value associated withhemolysis. However, implantable pump 2 described herein may be sized andconfigured to achieve various other flow rates at pressure gradientslower than a threshold value associated with hemolysis. Also, to mimic atypical physiological pulse of 60 beats per minute, implantable pump 2may pulse about once per second. To achieve such pulsatility, a dutycycle of 50% may be utilized with an “on” period of 0.5 seconds and an“off” period of 0.5 seconds. For a given system, maximum efficiency at aspecific operating frequency, amplitude and voltage may be achievedwhile producing a flow rate of 1 to 3 liters per minute at a duty cycleof 50% by manipulating one or more of the shape and size of blood flowchannels and gaps, elastic properties of spring system, mass of themoving parts, membrane geometries, and elastic properties and frictionproperties of the membrane. In this manner, implantable pump 2 may bedesigned to produce desirable outputs to partially support physiologicalcirculation while continuing to function at optimum operatingparameters.

By adjusting the duty cycle, implantable pump 2 may be configured togenerate a wide range of output flows at physiological pressuregradients. For example, pump system 1 may be configured to produce 1 to3 liters per minute at a duty cycle of 50%, optimal operating frequencymay be 120 Hz. For this system, flow output may be increased to 3 litersper minute or decreased to 1 liters per minute, for example, by changingonly the duty cycle. As duty cycle and frequency operate independent ofone another, duty cycle may be manipulated between 0 and 100% whileleaving the frequency of 120 Hz unaffected.

The implantable pump system described herein may be tuned to achievepartial-support flow rates and physiological pressure gradients andpulsatility while avoiding hemolysis and platelet activation by applyinglow to moderate shear forces on the blood, similar to those exerted by ahealthy heart. The moving components are rigidly affixed to one anotherand do not incorporate any parts that would induce friction, such asmechanical bearings or gears. Inlet channel 71 and upper flow channel 72and lower flow channel 73 are sized and configured to also avoidfriction by sizing the channels and gaps such that clearances of atleast 0.5 mm are maintained between all moving components. Similarly,magnet 51 is sized and configured to be separated by at least 0.5 mmfrom non-moving components such as mounting structure 44 to avoidfriction.

Other embodiments of pump system 1 may include fewer or additionalcomponents or components having different shapes or sizes. For example,FIG. 14 illustrates an implantable housing 12′ that narrows from inlet13′ toward outlet 14′. In this configuration, the rectangular membranemay be disposed therein and similarly narrow as it nears outlet 14′. Inthis embodiment, the narrowing of implantable housing 12′ may helpdirect the blood flow out of outlet 14′.

Other embodiments may employ an electromagnetic actuator having magnetsand electromagnetic portions different than those described in FIGS.4-13 . For example, FIG. 15 illustrates an alternative embodiment of thepump assembly. Pump assembly 16′, shown in FIG. 15 , includeselectromagnetic assembly 42′, magnet assembly 41′, first supportstructure 61, second support structure 62, membrane holder 59 andrectangular membrane 48. Membrane holder 59 is configured to be disposedwithin and mounted to implantable housing 12 using screws, welding orany other well-known technique appropriate for rigidly coupling membraneholder 59 to implantable housing 12. Membrane holder 59 is configured tosupport electromagnetic assembly 42′ and rectangular membrane 48.

First support structure 61 and second support structure 62 are alsoconfigured to be disposed within and mounted to implantable housingusing any well-known technique such as screws or welding. First supportstructure 61 and second support structure 62 each may support a portionof magnet assembly 41′ having one or more positive permanent magnets andnegative permanent magnets. Magnet assembly 41′ may be mounted to firstsupport structure 61 and second support structure 62 such that amagnetic field is generated at a top end of first support structure 61and second support structure 62 and a magnetic field having an oppositepolarity is generated near a bottom end of first support structure 61and second support structure 62. First support structure 61 and secondsupport structure 62 may be mounted to implantable housing 12 such thata gap exists between the two that is sufficiently large enough forelectromagnetic assembly 42′ to fit between and move in a plane parallelto the gap.

Membrane holder 59 may be flexible and may permit electromagneticassembly 42′ to move up toward the first magnetic field and down towardthe second magnetic field. As electromagnetic assembly 42′ moves up anddown, an end of membrane 48 coupled to electromagnetic assembly 42′ isalso caused to move up and down. Also, as electromagnetic assembly 42′moves up and down, membrane holder 59 is elastically deformed andapplies a spring force is to electromagnetic assembly 42′ to returnelectromagnetic assembly 42′ to the neutral position where membraneholder 59 is not deformed.

As the end of rectangular membrane 48 moves up and down, wavelikedeformations are propagated along membrane 48 toward outlet 14, asdescribed above. In this embodiment, current applied to electromagneticassembly 42′ causes electromagnetic assembly 42′ to move up and downwhile magnet assembly 41′ stays stationary. Unlike the embodiment wheremagnet 51 moves, in the embodiment illustrated in FIG. 15 ,electromagnetic assembly 42′ may be attracted to and thus move towardone magnetic field by inducing current in one direction, and conversely,may be attracted to and thus move in the other direction towards theother magnetic field, having an opposite polarity, by inducing currentin the opposite direction.

Another embodiment of the electromagnetic actuator is illustrated inFIG. 16 . In FIG. 16 , an alternative system for propagating waves inthe membrane is described. As is shown in FIG. 16 , this alternativesystem may include rectangular membrane 75, first magnet 79, first coil78, and first ferromagnetic casing 81 as well as second magnet 80,second coil 77, and second ferromagnetic casing 82. First magnet 79 andsecond magnet 80 are connected by rod 76 which is also coupled tomembrane 75. First coil 78 and second coil 77 may be connected tocontroller 3 and/or battery 4. Controller may induce, and alternate,current in first coil 78 and second coil 77 which causes first magnet 79and second magnet 80 to move up and down in tandem. As first magnet 79and second magnet 80 move up and down, rod 76 may be moved up and downcausing the portion of membrane 75 connected to rod 76 to move up anddown. In this manner, membrane 75 may be caused to undulate. Membrane 75may vary in thickness as it moves from one end to another. Thealternative electromagnetic actuator shown in FIG. 16 may be designedand configured to fit within pump housing 12 and function as a bloodpump in the manner described herein.

Referring now to FIG. 17 , an electromechanical actuator embodiment isillustrated. The system shown in FIG. 17 includes rectangular membrane95, rod 96, guide 97, cam 98, an assembly of coil 99, rotating magnet100, the combination of 99 and 100 forming an asynchronous motor, andconnector 101. Coil 99 may be in electrical communication withcontroller 3 and/or battery 4 and may be energized to move in rotationmagnet 100 on the same axis as coil 99. Rotating magnet 100 may beconnected to connector 101 which is connected to cam 98 at the otherend. Membrane 95 is connected at one end to rod 96. Rod 96 is connectedto cam 98 at one end and is guided by guide 97 so that rod 96 is onlyfree to move along its longitudinal axis. As rotating magnet 100 iscaused by the magnetic field generated by coil assembly 99, the movementof rotation of magnet 100 is transmitted by cam 98 via connector 101 torod 96 which moves up and down its longitudinal axis. As rod 96 moves upand down its longitudinal axis, the end of membrane 95 that is connectedto rod 96 moves up and down causing wave-like deformations to propagatealong membrane 95. The alternative electromechanical actuator shown inFIG. 17 may be designed and configured to fit within pump housing 12 andfunction as a blood pump in the manner described herein.

Referring now to FIG. 18A-18C, implantable pump 102, which may be usedin system 1 in place of implantable pump 2, is illustrated in greaterdetail. Implantable pump 102 includes pump housing 112 which is made ofa biocompatible material, such as titanium, and is sized to be implantedwithin a patient's chest as described above. Pump housing 112 may be twoor more pieces that fit together by, for example, threads or welding, toform fluid tight pump housing 112. In one embodiment, pump housing 112is sized and configured to have a length between 60-80 mm, a widthbetween 30-60 mm and a height between 7-15 mm. However, pump housing 112may have any other size suitable for pump assembly 116 to be disposedwithin pump housing 112. Pump housing includes inlet 113 and outlet 114through which blood may flow in and out, respectively. Pump also mayinclude electrical port 115 to attach implantable pump 102 to cable 109.Electrical port 115 may permit cable 109 to transverse pump housing 112and connect to pump assembly 116 in a fluid tight manner. Cable 109 maydeliver electrical wires from controller 3 and battery 4 to pumpassembly 116.

Referring to FIGS. 19A and 19B, pump assembly 116 is illustrated ingreater detail. Pump assembly 116 may include membrane assembly 149,magnet assembly 141, electromagnetic assembly 142, fixation elements 144and 145, and funnel assembly 150. Membrane assembly 149 may includemounting structure 146, membrane holder 147 and rectangular membrane148. Electromagnetic assembly 142 may include first coil 157 and secondcoil 158 each having an electromagnetic winding. Magnet assembly 141 mayinclude upper magnet unit 151 and a lower magnet unit 152.

Pump assembly 116 is sized and configured to fit within pump housing112. Fixation elements 144 and 145, mounting structure 146 and funnelassembly 150 may be mounted to pump housing 112 using any well-knownfixation technique. For example, fixation elements 144 and 145, mountingstructure 146, funnel assembly 150 may include threaded grooves thatcorrespond to threaded grooves in pump housing 112 and may be coupled topump-housing 112 using plurality of screws. Alternatively, fixationelements 144 and 145, mounting structure 146, funnel assembly 150 may bewelded to pump housing 112.

Referring now to FIG. 20 , an exploded view of pump assembly 116 isillustrated. As is shown in FIG. 20 , upper magnet unit 151 and lowermagnet unit 152 may include a number of smaller magnets, oralternatively may include only a single magnet. As is also shown in FIG.20 , both upper magnet unit 151 and lower magnet unit 152 may berectangular in shape and may be sized and configured to be supported byfunnel assembly 150. Upper magnet unit 151 and lower magnet unit 152also may be secured to pump housing 112 and may include a securingportion designed to secure upper magnet unit 151 and lower magnet unit152 to pump housing 112.

Funnel assembly 150 may include upper funnel 153 and lower funnel 154,as is illustrated in FIG. 20 . Upper funnel 153 and lower funnel 154 mayinclude a flanged portion for supporting upper magnet unit 151 and lowermagnet unit 152, respectively. Upper funnel 153 may have an uppersurface secured to pump housing 112 and lower funnel 154 may have alower surface secured to pump housing 112. When lower funnel 154 andupper funnel 153 are secured to the pump housing, a gap exists betweenlower funnel 154 and upper funnel 153, as is illustrated in FIG. 19A.

Between lower funnel 154 and upper funnel 153 rectangular membrane 148is suspended and may extend the length of upper funnel 153 and lowerfunnel 154. Posts 155 and 156 extend between upper funnel 153 and lowerfunnel 154 near a distal end of upper funnel 153 and lower funnel 154adjacent to outlet 114 of pump housing 112. Posts 155 and 156 arepositioned in a parallel fashion and are separated a sufficient distanceto permit fluid flow between them. Rectangular membrane 148 is connectedto posts 155 and 156 at a distal end of rectangular membrane 148.Rectangular membrane 148 may have two holes in the distal end ofrectangular membrane 148 that are sized and configured to receive posts155 and 156. Posts 155 and 156 may further include connection elementsthat move freely along posts 155 and 156 and serve to anchor rectangularmembrane 148 to posts 155 and 156.

As is shown in FIG. 20 as well as FIGS. 19A and 19B, membrane holder 147is positioned at the distal end of rectangular membrane 148. As isillustrated in FIG. 20 , membrane holder 147 is also positioned betweenupper magnet unit 151 and lower magnet unit 152. Additionally, membraneholder 147 is positioned between first coil 157 and second coil 158.Membrane holder 147 may be designed to couple to membrane clamp 159. Tosecure rectangular membrane 148 to membrane holder 147, a proximal endof rectangular membrane 148 may be placed over an end of membrane holder147 designed to received rectangular membrane 148. Subsequently,membrane clamp 159 may be placed over the portion of rectangularmembrane 148 that is covering membrane holder 147 and clamped orotherwise secured to membrane holder 147. Membrane clamp 159 may bedesigned to snap into membrane holder 147 or otherwise screw intomembrane holder 147. In this manner, rectangular membrane 148 may besecured to membrane holder 147. Alternatively, rectangular membrane 148may secured to membrane holder 147 without the use of membrane clamp 159using a number of well-known securing techniques, e.g. epoxy, screws,etc. At a proximal end of membrane holder 147, membrane holder 147 issecured to mounting structure 146. As explained above, mountingstructure 146 is secured to pump housing 112.

First coil 157 and second coil 158 of electromagnetic assembly 142 mayinclude one or more smaller metallic wires that may be wound into acoil, and may be in electrical communication with battery and/orcontroller via cable 9 connected via electrical port 115. First coil 157and second coil 158 may be in electrical communication with one anotherand/or may be configured to operate independently and have separatewired connections to controller 3 and/or battery 4 via cable 9. Currentflow applied to first coil 157 and second coil 158 could be reverseddepending on the operating parameters applied. The wires of first coil157 and second coil 158 may be insulated to prevent shorting to adjacentconductive material.

First coil 157 and second coil 158 may include membrane holder receivingportions 150 for securing a portion of the distal end of membrane holder147 to first coil 157 on one side and second coil 158 on the other side.In this manner, first coil 157 and second coil 158 are supported only bymembrane holder 147 which is mounted on mounting structure 146. Theconnection between first coil 157 and second coil 158 and membraneholder 147 may further include a spring system to reduce resonanceeffects. First coil 157 and second coil 158 are positioned relative tomembrane holder 147 such that upper magnet unit 151 and lower magnetunit 152 are positioned between first coil 157 and second coil 158 butdo touch coil 157 and second coil 158. First coil 157 and second coil158 may be sized such that upper funnel 153 and lower funnel 154 arepositioned between first coil 157 and second coil 158 without touchingfirst coil 157 and second coil 158.

Fixation elements 144 and 145 may be secured to pump housing 112 suchthat first coil 157 and second coil 158 are positioned between fixationelements 144 and 145 without touching fixation elements 144 and 145.Fixation elements 144 and 145 may have magnetic properties and thus mayloop the magnet field created by magnet assembly 141 and otherwisecontribute to the magnetic force generated. In this manner, first coil157 is positioned between fixation element 145 on one side and on theother side magnet assembly 141, membrane holder 147, rectangularmembrane 148 and funnel assembly 150. Similarly, second coil 158 ispositioned between fixation element 144 on one side and on the otherside magnet assembly 141, membrane holder 147, rectangular membrane 148and funnel assembly 150 on the other side. Also, in this configuration,rectangular membrane 148 is suspended within funnel assembly 150,membrane holder 147 is suspended within magnet assembly 141 rectangularmembrane 148 and membrane holder 147 are surrounded on either side byfirst coil 157 and second coil 158.

Implantable pump housing 112, fixation elements 144 and 145, mountingstructure 146, and funnel assembly 150 may be comprised of titanium,stainless steel or any other rigid biocompatible material suitable formounting pump assembly 116 to pump housing 112. These components may beinsulated and/or made of non-conductive material to reduce unwantedtransmission of the electrical signal. Magnet assembly 141 may becomprised of one or more materials exhibiting magnetic properties suchas iron, nickel, cobalt or various alloys. Where multiple magnets makeup magnet assembly 141, the magnets may be linked by metallic parts madeof a high saturation alloy, such as Vacoflux. Mounting structure too maybe made from Vacoflux. The one or more smaller metallic wires wound intoa coil in electromagnetic assembly 142 may be made of copper or anyother metal having appropriate electromagnetic properties.

Referring now to FIGS. 21A and 21B, a portion of funnel assembly 150 isillustrated. The funnel portion illustrated may be either upper funnel153 and lower funnel 154 as these units may be interchangeable. As isillustrated in FIGS. 21A and 21B, the thickness of the funnel portionincreases as it moves towards narrows funnel outlet 161. As is alsoillustrated in FIGS. 21A and 21B, the width of the flow channel creasedby the flow channel narrows as it moves towards funnel outlet 161. Thefunnel may include flanged portion 162 designed to support at least aportion of magnetic assembly 141 and secure at least a portion ofmagnetic assembly 141 to pump housing 112. Upper funnel 153 and lowerfunnel 154 also may include threaded portions 164 that extend thethrough upper funnel 153 and lower funnel 154 or at least partwaythrough and permit upper funnel 153 and lower funnel 154 to be securedto pump housing 112.

Referring now to FIGS. 22A and 22B, membrane holder 147 is illustrated.As is shown in these figures, membrane holder 147 may be generallyrectangular having mounting portion 165 and membrane securing portion166. Mounting portion 165 is designed to be secured to mountingstructure 146. As is shown in FIG. 22B, at least membrane securingportion 166 is designed to be flexible. As such, membrane securingportion 166 may flex up and down relative to mounting portion 165.Membrane holder 147, including at least membrane securing portion 166,may have elastic properties which exhibits a spring force when membranesecuring portion 166 is deflected relative to mounting portion 165.While, membrane securing portion 166 may flex when deformed up and downrelative mounting portion 165, membrane securing portion 166 may rigidlyresist movement along any other axis, e.g., tilt or twist movements.Membrane holder 147 may be made from any metal or material having theproperties just described.

In one embodiment, membrane holder 147 and/or membrane clamp 159 mayexhibit electromagnetic properties. For example, membrane holder 147and/or membrane clamp 159 may be in electrical communication withelectromagnetic assembly 142. As such when electromagnetic assembly 142is electrically activated, membrane holder 147 and/or membrane clamp 159may too become electrically activated and thus generate a magnetic fielddue to their electromagnetic properties. In generating anelectromagnetic field, membrane holder 147 and/or membrane clamp 159 maybecome attracted to either upper magnet unit 151 or lower magnet unit152.

Referring now to FIGS. 23A-23C, rectangular membranes similar to thosedescribed above in FIGS. 10A-10C are illustrated. Thus, the descriptionof the rectangular membranes in FIGS. 23A-23C can be referred to above.In general, rectangular membrane 148 may take a general thin rectangularshape. In a preferred embodiment, rectangular membrane 148 has a thin,planar shape and is made of an elastomer having elastic properties andgood durability. Rectangular membrane 148 may have a uniform thicknessfrom one end to the other. As yet a further alternative, rectangularmembrane 148 may vary in thickness and exhibit more complex geometries.For example, rectangular membrane 148 may have a reduced thickness asthe membrane extends from one end to the other. Alternatively, or inaddition to, rectangular membrane 148 may incorporate metallic elementssuch as a spring to enhance the spring force of the membrane in adirection normal to plane of the membrane. In yet another embodiment,rectangular membrane 148 may be pre-formed with an undulating shape.

As is illustrated in FIG. 23A, rectangular membrane 148 may have twopost receiving portions 167 and 168. Post receiving portions 167 and 168may have a diameter slightly larger than that of posts 155 and 156.Also, as shown in FIG. 23A, rectangular membrane 148 may have extendedportions 169 and 170. Extended portions 169 and 170 may permit fluid tomore freely escape out of outlet 114 of implantable pump 102.Alternatively, in FIG. 23B, rectangular membrane 148′ having two postreceiving portions 167′ and 168′ may extend the entire length of themembrane without any extended portions. In yet another alternative, asshown in FIG. 23C, rectangular membrane 148″ may not include the postreceiving portions. This may permit the distal end of rectangularmembrane 148″ nearest outlet 114 to move more freely.

Referring now to FIGS. 24A and 24B, sectional views of implantable pump102 are illustrated. In FIG. 24A, rectangular membrane 148 and membraneholder 147 are seen suspended between upper funnel 153 and upper magnetunit 151 above, and lower funnel 154 and lower magnet unit 152 below.Rectangular membrane 148 is shown being held in tension between membraneholder 147 and posts 155 and 156. As is also shown in FIG. 24A, secondcoil 158 is suspended within implantable pump housing 112 by membraneholder 147 which is secured in a cantilevered configuration by mountingstructure 146.

From FIG. 24A it is clear that a flow channel exists between inlet 113and outlet 114. Specifically, blood may flow through inlet 113, over andaround mounting structure 146, and then flow toward outlet 114 betweenupper magnet unit 151 and a top surface of membrane holder 147 andmembrane 148 as well as between lower magnet unit 152 and a bottomsurface of membrane holder 147 and membrane 148. As the blood nears theoutlet, blood may then flow between a bottom surface of upper funnel 153and a top surface of membrane 148 as well as between a top surface oflower funnel 154 and a bottom surface of membrane 148. As blood flowsthrough funnel assembly 150, the flow channel begins to narrow.

Referring now to FIG. 24B, a sectional view along an orthogonal planefrom that shown in FIG. 24A is provided. As just described, blood mayenter from inlet 113 and travel along membrane holder 147 andrectangular membrane 148. As is shown in FIG. 24B, blood may flow in thespace between first coil 157 and second coil 158 and may even flowbetween first coil 157 and second coil 158 and fixation elements 145 and144, respectively. As will be described in greater detail below, firstcoil 157 and second coil 158 and fixation elements, membrane holder 147and rectangular membrane 148 all may move relative to pump housing 112.Conversely, mounting structure 146, magnet assembly 141, fixationelements 144 and 145, and funnel assembly 150 remain stationary relativeto pump housing 112. Thus, in accordance with one aspect of the presentinvention, the implantable pump described herein avoids thrombusformation by placing all moving parts directly within the primary flowpath, thereby reducing the risk of flow stagnation. Flow stagnation isfurther avoided by configuring all gaps in the flow path to be no lessthan 0.5 mm and also by eliminating secondary flow paths that mayexperience significantly slower flow rates.

Referring now to FIGS. 25A and 25B, implantable pump may be activated topump blood from inlet 113 to outlet 114 by moving first coil 157 andsecond coil 158 up and down relative to pump housing 112. Constrained byonly membrane holder 147, first coil 157 and second coil 158 may move upand down between membrane holder 147, rectangular membrane 148, magnetassembly 141 and funnel assembly 150 on one side and fixation elements144 and 145 on the other. To move first coil 157 and second coil 158 up,current may be applied to first coil 157 and second coil 158 such thatfirst coil 157 and second coil 158 generate a magnetic field that causesfirst coil 157 and second coil 158 to move toward upper magnet unit 151.Conversely, to move first coil 157 and second coil 158 down, current maybe applied to first coil 157 and second coil 158 such that first coil157 and second coil 158 generate an electric field that causes firstcoil 157 and second coil 158 to move toward lower magnet unit 152.

Upper magnet unit 151 and lower magnet unit 152 may have oppositepolarities such that when current is applied in one direction throughfirst coil 157 and second coil 158, first coil 157 and second coil 158are attracted to upper magnet unit 151, but when current is applied tofirst coil 157 and second coil 158 in the reverse direction, first coil157 and second coil 158 are attracted to lower magnet unit 152.

In FIG. 25A, current is flowing in first coil 157 and second coil 158such that first coil 157 and second coil 158 are attracted to uppermagnet unit 151. First coil 157 and second coil 158 may be activated bycontroller 3 by applying an electrical signal from battery 4 to firstcoil 157 and second coil 158, thus inducing current in the first coil157 and second coil 158 and generating a magnetic field surroundingfirst coil 157 and second coil 158. As membrane holder 147 includes aflexible portion to which first coil 157 and second coil 158 are securedto and suspended by, first coil 157 and second coil 158 are free to moveup toward upper magnet unit 151. Similarly, should the direction ofcurrent be reversed in first coil 157 and second coil 158, first coil157 and second coil 158 would be attracted to lower magnet unit 152 andthus move down toward lower magnet unit 152.

As membrane holder 147 exhibits a spring force when elastically deformedin a direction normal to a longitudinal plane of membrane holder 147,when first coil 157 and second coil 158 move up toward upper magnet unit151, membrane holder 147 exerts a downward spring force on first coil157 and second coil 158 toward the neutral position. Similarly, whenfirst coil 157 and second coil 158 move downward toward lower magnetunit 152, membrane holder 147 exerts an upward spring force on firstcoil 157 and second coil 158 toward the neutral position. The furtherfirst coil 157 and second coil 158 move from the undeflected neutralposition, the greater the spring force applied to first coil 157 andsecond coil 158.

By manipulating the timing and intensity of the electrical signalsapplied to electromagnetic assembly 142, the frequency at whichelectromagnetic assembly 142 moves up and down may be altered. Forexample, by alternating the current induced in the electromagneticassembly 142 more frequently, electromagnetic assembly 142 may be causedto cycle up and down more times in a given period. By increasing thevoltage applied, the electromagnetic assembly 142 may be deflected at afaster rate and caused to travel longer distances.

As first coil 157 and second coil 158 are rigidly coupled to an end ofmembrane holder 147 and rectangular membrane 148 is also coupled at thesame end of membrane holder 147, movement of first coil 157 and secondcoil 158 is applied to the end of rectangular membrane 148. FIGS. 25Aand 125B illustrate movement by first coil 157 and second coil 158 beingapplied to rectangular membrane 148. As is shown in FIG. 25A, a currenthas been induced in first coil 157 and second coil 158 such that firstcoil 157 and second coil 158 are attracted to upper magnet unit 151. Themovement of first coil 157 and second coil 158 has caused membranesecuring portion 166 to move upward with first coil 157 and second coil158. In FIG. 25A, the deformation in membrane holder 147 can clearly beseen. As can also be seen, rectangular membrane 148 has traveled upwardwith membrane securing portion 166.

As rectangular membrane 148 is attached to the same portion of membraneholder 147 as first coil 157 and second coil 158, when first coil 157and second coil 158 travel a certain distance upward or downward, theend of rectangular membrane 148 attached to membrane holder 147 alsotravels the same distance. For example, when first coil 157 and secondcoil 158 travel 4 mm above the neutral position of membrane holder 147,the end of rectangular membrane 148 attached to membrane holder 147 alsotravels 4 mm in the same direction. Similarly, the frequency at whichfirst coil 157 and second coil 158 reciprocates up and down is the samefrequency at which rectangular membrane 148 travels the same distance.Preferably, the frequency is between 0 to 150 Hz, though otherfrequencies may be achieved using the system described herein.

Referring now to FIG. 25B, and as is illustrated in FIGS. 2 and 3 anddescribed above, blood enters implantable pump 102 from inlet cannula 7extending into the left atrium and flows into inlet 113 directly intodelivery channel 171. As the blood moves toward outlet 114 it isdirected through gap 172 between upper magnet unit 151 and lower magnetunit 152 and then into gap 173 between upper funnel 153 and lower funnel154. By directing blood from delivery channel 171 to gap 172 blood isdelivered to rectangular membrane 148. By inducing alternating currentto first coil 157 and second coil 158, membrane 148 may be undulatedbetween gaps 172 and 173 to induce wavelike formations in rectangularmembrane 148 that moves from the edge of rectangular membrane 148coupled to membrane holder 147 towards outlet 114. Accordingly, whenblood is delivered to rectangular membrane 148 from delivery channel171, it is propelled along both the top and bottom of rectangularmembrane 148 and ultimately out of outlet 114. The waves formed in theundulating rectangular membrane may be manipulated by changing the speedat which first coil 157 and second coil 158 move up and down as well asthe distance first coil 157 and second coil 158 move up and down. Thetransfer of energy from the membrane to the blood is directed along thelength of the membrane towards outlet 114, and propels the blood alongboth sides of rectangular membrane 148.

FIG. 25B shows that when membrane securing portion 166 moves upward, thelower portion of gap 172 below membrane holder 147 and rectangularmembrane 148 expands, causing blood to fill the lower portion of gap172. As membrane securing portion 166 moves downward, the lower portionof gap 172 begins to narrow toward outlet 114, causing wave-likedeformations to translate across the membrane. As the wave propagatesacross rectangular membrane 148, blood in the lower portion of gap 172is propelled towards gap 173 and ultimately out of implantable pump 102.As blood moves toward outlet 14 within gap 173, gap 173 narrowsaccelerating the blood towards the outlet. Simultaneously, as membranesecuring portion 166 moves downwards, the upper portion of gap 172 abovethe top surface of rectangular membrane 148 and membrane holder 147,begins to enlarge, allowing blood from delivery channel 171 to flow intothis region. Subsequently, when membrane securing portion 166 is againthrust upwards, the upper portion of gap 172 begins to narrow, causingwave-like deformations to propagate across the membrane, propellingblood towards outlet 114. Preferably, the speed of the wave propagationis 1 to 1.5 m/s, though other propagation speeds may be achieved usingthe system described herein.

By manipulating the waves formed in the undulating membrane by changingthe frequency and amplitude at which membrane securing portion 166 movesup and down, the pressure gradient within gap 172 and gap 173 andultimately the flow rate of the blood moving through implantable pump102 may be adjusted. Appropriately controlling the membrane securingportion 166 permits oxygen-rich blood to be effectively and safelypumped from the left atrium to the right subclavian artery andthroughout the body as needed. While the pump described herein isdescribed as pumping blood from the left atrium to the right subclavianartery, the implantable pump described herein could be used to pumpblood from and to different areas, e.g. from the left ventricle to theaorta.

In addition to merely pumping blood from the left atrium to thesubclavian artery, implantable pump 102 of the present invention may beoperated to closely mimic physiologic pulsatility, without loss of pumpefficiency. Pulsatility may be achieved nearly instantaneously bychanging the frequency and amplitude at which membrane securing portion166 moves, to create a desired flow output, or by ceasing movement ofthe electromagnetic assembly 142 for a period time to create a period oflow or no flow output. Unlike typical rotary pumps, which require acertain period of time to attain a set number of rotations per minute toachieve a desired fluid displacement and pulsatility, implantable pump102 may achieve a desired flow output nearly instantaneously andsimilarly may cease output nearly instantaneously due to the very lowinertia generated by the small moving mass of the moving components ofthe pump assembly. The ability to start and stop on-demand permits rapidchanges in pressure and flow. Along with the frequency and amplitude,the duty cycle, defined by the percentage of time rectangular membrane148 is excited over a set period of time, may be adjusted to achieve adesired flow output and pulsatility, without loss of pump efficiency.Even holding frequency and amplitude constant, flow rate may be alteredby manipulating the duty cycle between 0 and 100%.

In accordance with another aspect of the invention, controller 3 may beprogrammed by programmer 5 to operate at selected frequencies,amplitudes and duty cycles to achieve a wide range of physiologic flowrates and with physiologic pulsatilities. For example, programmer 5 maydirect controller 3 to operate implantable pump 102 at a givenfrequency, amplitude and/or duty cycle during a period of time when apatient is typically sleeping and may direct controller 3 to operateimplantable pump 102 at a different frequency, amplitude and or dutycycle during time periods when the patient is typically awake.Controller 3 or implantable pump 102 also may include an accelerometeror position indicator to determine whether the patient is supine orambulatory, the output of which may be used to move from one set of pumpoperating parameters to another. When the patient experiences certaindiscomfort or a physician determines that the parameters are notoptimized, physician may alter one or more of at least frequency,amplitude and duty cycle to achieve the desired functionality.Alternatively, controller 3 or mobile device 6 may be configured toalter one or more of frequency, amplitude and duty cycle to suit thepatient's needs.

Implantable pump 102 further may comprise one or more additional sensorsfor adjusting flow output and pulsatility according to the demand of thepatient. Sensors may be incorporated into implantable pump 102 oralternatively or in addition to may be implanted elsewhere in or on thepatient. The sensors preferably are in electrical communication withcontroller 3, and may monitor operational parameters that measure theperformance of implantable pump 102 or physiological sensors thatmeasure physiological parameters of the patients such as heart rate orblood pressure. By using one or more physiological sensors, pulsatileflow may be synchronized with a cardiac cycle of the patient bymonitoring blood pressure or muscle contractions, for example, andsynchronizing the duty cycle according to the sensed output.

Controller 3 may compare physiological sensor measurements to currentimplantable pump output. If it is determined by analyzing sensormeasurements that demand exceeds current output, frequency, amplitudeand/or duty cycle may be automatically adjusted to meet current demand.Similarly, the controller may determine that current output exceedsdemand and thus alter output by changing frequency, amplitude and/orduty cycle. Alternatively, or in addition to, when it is determined thatdemand exceeds current output, an alarm may sound from controller 3.Similarly, operational measurements from operational sensors may becompared against predetermined thresholds and where measurements exceedpredetermined thresholds or a malfunction is detected, an alarm maysound from controller 3.

Implantable pump 102 is sized and shaped to produce physiological flowrates, pressure gradients and pulsatility at an operating point at whichmaximum efficiency is achieved. Preferably, implantable pump 102 issized and shaped to achieve flow rates ranging from 1 to 3 liters perminute at pressure gradients lower than a threshold value associatedwith hemolysis. However, implantable pump 102 described herein may besized and configured to achieve various other flow rates at pressuregradients lower than a threshold value associated with hemolysis. Also,to mimic a typical physiological pulse of 60 beats per minute,implantable pump 102 may pulse about once per second. To achieve suchpulsatility, a duty cycle of 50% may be utilized with an “on” period of0.5 seconds and an “off” period of 0.5 seconds. For a given system,maximum efficiency at a specific operating frequency, amplitude andvoltage may be achieved while producing a flow rate of 1 to 3 liters perminute at a duty cycle of 50% by manipulating one or more of the shapeand size of blood flow channels and gaps, elastic properties of themembrane holder, mass of the moving parts, membrane geometries, andelastic properties and friction properties of the membrane. In thismanner, implantable pump 102 may be designed to produce desirableoutputs to partially support physiological circulation while continuingto function at optimum operating parameters.

By adjusting the duty cycle, implantable pump 102 may be configured togenerate a wide range of output flows at physiological pressuregradients. For example, pump system 1 may be configured to produce 1 to3 liters per minute at a duty cycle of 50%, optimal operating frequencymay be 120 Hz. For this system, flow output may be increased to 3 litersper minute or decreased to 1 liters per minute, for example, by changingonly the duty cycle. As duty cycle and frequency operate independent ofone another, duty cycle may be manipulated between 0 and 100% whileleaving the frequency of 120 Hz unaffected.

The implantable pump system described herein may be tuned to achievepartial-support flow rates and physiological pressure gradients andpulsatility while avoiding hemolysis and platelet activation by applyinglow to moderate shear forces on the blood, similar to those exerted by ahealthy heart. The moving components are rigidly affixed to one anotherand do not incorporate any parts that would induce friction, such asmechanical bearings or gears. Delivery channel 171 and gaps 172 and 173are sized and configured to also avoid friction by sizing the channelsand gaps such that clearances of at least 0.5 mm are maintained betweenall moving components. Similarly, first electromagnet 157 and secondelectromagnet 158 and membrane holder 147 are sized and configured to beseparated by at least 0.5 mm from non-moving components to avoidfriction.

Other embodiments of pump system 1 may include fewer or additionalcomponents. For example, FIG. 26 illustrates an alternative embodimentwherein pump assembly 116′ includes electromagnetic assembly 142′ havingonly one electromagnet positioned between magnet assembly 141′. Magnetassembly 141′ has an upper magnet unit with a gap in the middle and alower magnet unit with a gap in the middle. Pump assembly 116′ alsoincludes modified membrane holder 147′ which is coupled to mountingstructure 146 at a proximal end, coupled to the electromagnetic assembly142′ at a mid-section and coupled to rectangular membrane 148 at adistal end. As electromagnetic assembly 142′ is electrically activatedand attracted to lower magnet unit and upper magnet unit of magnetassembly 141′, electromagnetic assembly 142′ moves up and down throughthe gaps in magnet assembly 141′. Like in the embodiment describedabove, as modified membrane holder 147′ moves up and down withelectromagnetic assembly 142′, the end of rectangular membrane 148coupled to modified membrane holder 147′ also travels up and down,thereby deforming rectangular membrane 148 and propagating wavelikedeformations toward outlet 114. In this embodiment, though thedisplacement of rectangular membrane 148 is proportional to thedisplacement of electromagnetic assembly 142′, the displacement may notbe the same depending on the design of modified membrane holder 147′.

Other embodiments may employ an electromagnetic actuator having magnetsand electromagnetic portions different than those described in FIGS.18A-26 . For example, in FIG. 27 an alternative system for propagatingwaves in the membrane is described. As is shown in FIG. 27 , thisalternative system may include membrane 175, first magnet 179, firstcoil 178, and first ferromagnetic casing 181 as well as second magnet180, second coil 177, and second ferromagnetic casing 182. First magnet179 and second magnet 180 are connected by rod 176 which is also coupledto membrane 175. First coil 178 and second coil 177 may be connected tocontroller 3 and/or battery 4. Controller may induce, and alternate,current in first coil 178 and second coil 177 which causes first magnet179 and second magnet 180 to move up and down in tandem. As first magnet179 and second magnet 180 move up and down, rod 176 may be moved up anddown causing the portion of membrane 175 connected to rod 176 to move upand down. In this manner, membrane 175 may be caused to undulate.Membrane 175 may vary in thickness as it moves from one end to another.The alternative electromagnetic actuator shown in FIG. 27 may bedesigned and configured to fit within pump housing 112 and function as ablood pump in the manner described herein.

Referring now to FIG. 28 , another electromagnetic actuator embodimentis illustrated. The system shown in FIG. 28 includes membrane 183, barmagnet 184, first coil 185, second coil 186, posts 202 and ferromagnetichousing 187. In this embodiment, first coil 185 and second coil 186 maybe in communication with controller 3 and/or battery 4. First coil 185and second coil 186 may be designed to receive an electrical signal thatattracts bar magnet 184. First coil 185 and second coil 186 also may bedesigned to repel bar magnet 184. For example, first coil 185 mayreceive an electrical signal that causes first coil 185 to attract barmagnet 184 while at the same time, second coil 186 may receive anelectrical signal that causes second coil 186 to repel bar magnet 184.By alternating the current applied to first coil 185 and second coil186, bar magnet 184 is caused to move up and down along posts 202towards and away from first coil 185 and second coil 186. Bar magnet 184may be coupled to membrane 183 along the perimeter of one end ofmembrane 183. As bar magnet 184 moves up and down posts 202, the end ofmembrane 183 coupled to bar magnet 184 may move up and down causingwave-like deformations that propagate along membrane 183. Thealternative electromagnetic actuator shown in FIG. 28 may be designedand configured to fit within pump housing 112 and function as a bloodpump in the manner described herein.

Referring now to FIG. 29 , another electromechanical actuator embodimentis illustrated. The system shown in FIG. 29 includes membrane 195, rod196, guide 197, cam 198, an assembly of coil 199, rotating magnet 200,the combination of 199 and 200 forming an asynchronous motor, andconnector 201. Coil 199 may be in electrical communication withcontroller 3 and/or battery 4 and may be energized to move in rotationmagnet 200 on the same axis as coil 199. Rotating magnet 200 may beconnected to connector 201 which is connected to cam 198 at the otherend. Membrane 195 is connected at one end to rod 196. Rod 196 isconnected to cam 198 at one end and is guided by guide 197 so that rod196 is only free to move along its longitudinal axis. As rotating magnet200 is caused to rotate by the magnetic field generated by coil assembly199, the movement of rotating magnet 200 is transmitted by cam 198 viaconnector 201 to rod 196 which moves up and down its longitudinal axis.As rod 196 moves up and down its longitudinal axis, the end of membrane195 that is connected to rod 196 moves up and down causing wave-likedeformations to propagate along membrane 195. The alternativeelectromechanical actuator shown in FIG. 29 may be designed andconfigured to fit within pump housing 112 and function as a blood pumpin the manner described herein.

Referring now to FIGS. 30A-30H, various configurations for energizingimplantable pump 2 or 102 described above are provided. As shown in FIG.30A, controller 3 includes output port 18 which is electrically coupledto cable 9 as described above, which in turn is coupled to implantablepump 2 or 102. Controller 3 also includes power connector 203, which maybe electrically coupled to a battery, an extension port electricallycoupled to a battery, or an AC/DC power supply. For example, powerconnector 203 may be male, while the connector of the correspondingbattery or extension port is female.

In one embodiment, as shown in FIG. 30B, controller 3 includes two powerconnectors, e.g., first power connector 203 and second power connector204. As described above, first power connector 203 may be electricallycoupled to a first battery, a first extension port electrically coupledto a first battery, or a first AC/DC power supply, and second powerconnector 203 may be electrically coupled to a second battery, a secondextension port electrically coupled to a second battery, or a secondAC/DC power supply. In this embodiment, first power connector 203 andsecond power connector 204 may both be male. In addition, controller 3includes circuitry for switching between power sources such that energyis selectively transmitted to controller 3 from at least one of thefirst or second battery/power supply. For example, the circuitry mayswitch between a first and second battery intermittently, or after theremaining power level of one of the batteries reaches a predeterminedthreshold.

Referring now to FIGS. 30C-E, configurations are illustrated whereincontroller 3 is directly electrically coupled to battery 4, such thatcontroller 3 and battery 4 may be worn by the patient together, e.g.,via a purse, shoulder bag, or holster. As shown in FIG. 30C, controller3 of FIG. 30A may be electrically coupled to battery 4 via powerconnector 203, wherein power connector 203 is male and battery 4 has acorresponding female connector. For example, FIG. 30D illustratescontroller 3 electrically coupled to battery 4, wherein battery 4 has asmaller size, and therefore lower capacity, and FIG. 30E illustratescontroller 3 electrically coupled to battery 4, wherein battery 4 has alarger size, and therefore higher capacity. As will be understood by aperson of ordinary skill in the art, battery 4 may have various sizesdepending on the need of the patient.

Referring now to FIGS. 30F-H, configurations are illustrated whereincontroller 3 is remotely electrically coupled to battery 4, such thatthe weight and volume of controller 3 and battery 4 are distributed andmay be worn by the patient separately, e.g., via a belt or a vest. Asshown in FIG. 30F, cable 214, which electrically couples controller 3 tobattery 4, is electrically coupled to first power connector port 205 viastrain relief 206, which is a hardwired junction between cable 214 andfirst power connector port 205. Power connector port 205 includes powerconnector 207, which may be electrically coupled to a battery. Forexample, power connector 207 may be male, while the connector of thecorresponding battery is female.

As shown in FIG. 30G, controller 3 may be remotely electrically coupledto battery 4 via cable 214. Cable 214 is electrically coupled at one endto controller 3 via second power connector port 208 and strain relief215, which is a hardwired junction between cable 214 and second powerconnector port 208, and electrically coupled at another end to battery 4via first connector port 205 and strain relief 206. For example, powerconnector 203 of controller 3 may be male while the connector ofcorresponding second power connector port 208 is female, and powerconnector 207 of first power connector port 205 may be male while theconnector of corresponding battery 4 is female.

In one embodiment, as shown in FIG. 30H, controller 3 may be remotelyelectrically coupled to multiple batteries, e.g., battery 4A and battery4B, via a single second power connector port 208. As shown in FIG. 30H,second power connector port 208 includes first strain relief 215A andsecond strain relief 215B, such that controller 3 is remotelyelectrically coupled to battery 4A via cable 214A and remotelyelectrically coupled to battery 4B via cable 214B. Specifically, cable214A is electrically coupled at one end to controller 3 via second powerconnector port 208 and first strain relief 215A, and electricallycoupled at another end to battery 4A via first connector port 205A andstrain relief 206A, and cable 214B is electrically coupled at one end tocontroller 3 via second power connector port 208 and second strainrelief 215B, and electrically coupled at another end to battery 4B viafirst connector port 205B and strain relief 206B. In this embodiment,controller 3 may include circuitry for switching between battery 4A andbattery 4B such that energy is selectively transmitted to controller 3from at least one of battery 4A and battery 4B. For example, thecircuitry may switch between battery 4A and battery 4B intermittently,or after the remaining power level of one of the batteries reaches apredetermined threshold. Alternatively, controller 3 may receive energyfrom battery 4A and battery 4B simultaneously.

In another embodiment, as shown in FIG. 30I, controller 3 iselectrically coupled to AC/DC power supply 209, which may be pluggedinto an electrical outlet via AC plug 213, e.g., when the patient isresting bedside. Specifically, AC/DC power supply 209 is electricallycoupled to controller 3 via cable 214, such that cable 214 iselectrically coupled at one end to controller 3 via second powerconnector port 208 and strain relief 215, and electrically coupled atanother end to AC/DC power supply 209 via first power supply port 210.In addition, AC/DC power supply 209 is electrically coupled to plug 213via cable 212 and second power supply port 211.

Controller 3 may include an internal battery, such that the internalbattery powers controller 3 and implantable pump 2 or 102 during thetime required for battery 4 to be replaced and/or recharged.Accordingly, controller 3 may include circuitry for switching betweenpower sources such that energy is transmitted to controller 3 from theinternal battery while battery 4 is disconnected from controller 3, andfrom battery 4 when battery 4 is electrically coupled to controller 3.In addition, the circuitry may allow battery 4 to charge the internalbattery while also energizing implantable pump 2 or 102 until theinternal battery is recharged to a desired amount, at which point thecircuitry allows battery 4 to solely energize implantable pump 2 or 102.Similarly, when controller 4 is electrically coupled to AC/DC powersupply 209, the circuitry may allow AC/DC power supply 209 to charge theinternal battery while also energizing implantable pump 2 or 102 untilthe internal battery is recharged to a desired amount, at which pointthe circuitry allows AC/DC power supply 209 to solely energizeimplantable pump 2 or 102.

While various illustrative embodiments of the invention are describedabove, it will be apparent to one skilled in the art that variouschanges and modifications may be made therein without departing from theinvention. For example, pump system 1 may be ordered differently and mayinclude additional or fewer components of various sizes and composition.The appended claims are intended to cover all such changes andmodifications that fall within the true spirit and scope of theinvention.

What is claimed is:
 1. A method for pumping blood comprising: activatinga first electromagnetic coil and a second electromagnetic coil disposedwithin a pump housing to simultaneously induce a first current in thefirst electromagnetic coil and a second current in the secondelectromagnetic coil, the first electromagnetic coil and the secondelectromagnetic coil oriented with respect to a magnetic assemblydisposed in the pump housing such that the magnet assembly is disposedbetween the first electromagnetic coil and the second electromagneticcoil; wherein, the first current and the second current interact with amagnetic field generated by the magnetic assembly to excite arectangular membrane coupled to the magnetic assembly thereby inducing awave-like deformation in the rectangular membrane to pump blood from aninlet of the pump housing, along the rectangular membrane, and out anoutlet of the pump housing.
 2. The method of claim 1, wherein the firstcurrent and the second current are oriented in a direction to cause anattraction between the magnetic assembly and at least the firstelectromagnetic coil.
 3. The method of claim 1, wherein the firstcurrent and the second current cause the magnetic assembly coupled tothe rectangular membrane to move from a first position to a secondposition to induce the wave-like deformation in the rectangularmembrane.
 4. The method of claim 3, further comprising, after activatingthe first electromagnetic coil and the second electromagnetic coil tosimultaneously induce the first current in the first electromagneticcoil and the second current in the second electromagnetic coil,activating the first electromagnetic coil and the second electromagneticcoil to simultaneously induce a third current in the firstelectromagnetic coil and a fourth current in the second electromagneticcoil, the third current opposite the first current and the fourthcurrent opposite the second current.
 5. The method of claim 4, whereinthe third current and the fourth current cause the magnetic assemblycoupled to the rectangular membrane to move from the second positionback to the first position.
 6. The method of claim 1, further comprisingceasing activation of the first electromagnetic coil and the secondelectromagnetic coil to cause the magnetic assembly to return to aneutral position.
 7. The method of claim 1, wherein, the first currentand the second current interact with the magnetic field generated by themagnetic assembly to excite the rectangular membrane by causing themagnetic assembly to move from a neutral position to a displacedposition, and wherein a resisting force acts on the magnetic assemblywhen the magnetic assembly is in the displaced position.
 8. The methodof claim 1, wherein the first current and the second current interactwith the magnetic field generated by the magnetic assembly to excite therectangular membrane, causing the magnetic assembly to move from aneutral position to a displaced position, and wherein the magneticassembly is guided linearly by a guide post disposed within the housing.9. The method of claim 1, further comprising alternating the firstcurrent in the first electromagnetic coil and the second current in thesecond electromagnetic to change a speed at which the magnetic assemblymoves.
 10. The method of claim 1, further comprising alternating thefirst current in the first electromagnetic coil and the second currentin the second electromagnetic to change a distance which the magneticassembly moves.
 11. A non-transitory computer-readable memory mediumconfigured to store instructions thereon that, when executed by aprocessor, cause the processor to: cause a first electromagnetic coiland a second electromagnetic coil disposed within a pump housing toactivate simultaneously induce a first current in the firstelectromagnetic coil and a second current in the second electromagneticcoil, the first electromagnetic coil and the second electromagnetic coiloriented with respect to a magnetic assembly disposed in the pumphousing such that the magnet assembly is disposed between the firstelectromagnetic coil and the second electromagnetic coil; wherein, thefirst current and the second current interact with a magnetic fieldgenerated by the magnetic assembly to excite a rectangular membranecoupled to the magnetic assembly thereby inducing a wave-likedeformation in the rectangular membrane to pump blood from an inlet ofthe pump housing, along the rectangular membrane, and out an outlet ofthe pump housing.
 12. The non-transitory computer-readable memory mediumof claim 11, wherein the first current and the second current areoriented in a direction to cause an attraction between the magneticassembly and at least the first electromagnetic coil.
 13. Thenon-transitory computer-readable memory medium of claim 11, wherein thefirst current and the second current cause the magnetic assembly coupledto the rectangular membrane to move from a first position to a secondposition to induce the wave-like deformation in the rectangularmembrane.
 14. The non-transitory computer-readable memory medium ofclaim 13, wherein the instructions, when executed, after causing thefirst electromagnetic coil and the second electromagnetic coil tosimultaneously activate to induce the first current in the firstelectromagnetic coil and the second current in the secondelectromagnetic coil, cause the first electromagnetic coil and thesecond electromagnetic coil to simultaneously activate to induce a thirdcurrent in the first electromagnetic coil and a fourth current in thesecond electromagnetic coil, the third current opposite the firstcurrent and the fourth current opposite the second current.
 15. Thenon-transitory computer-readable memory medium of claim 14, wherein thethird current and the fourth current cause the magnetic assembly coupledto the rectangular membrane to move from the second position back to thefirst position.
 16. The non-transitory computer-readable memory mediumof claim 11, wherein the instructions, when executed, further cause thefirst electromagnetic coil and the second electromagnetic coil to ceaseactivation to cause the magnetic assembly to return to a neutralposition.
 17. The non-transitory computer-readable memory medium ofclaim 11, wherein, the first current and the second current interactwith the magnetic field generated by the magnetic assembly to excite therectangular membrane by causing the magnetic assembly to move from aneutral position to a displaced position, and wherein a resisting forceacts on the magnetic assembly when the magnetic assembly is in thedisplaced position.
 18. The non-transitory computer-readable memorymedium of claim 11, wherein the first current and the second currentinteract with the magnetic field generated by the magnetic assembly toexcite the rectangular membrane, causing the magnetic assembly to movefrom a neutral position to a displaced position, and wherein themagnetic assembly is guided linearly by a guide post disposed within thehousing.
 19. The non-transitory computer-readable memory medium of claim11, wherein the instructions, when executed, further cause the firstcurrent in the first electromagnetic coil and the second current in thesecond electromagnetic to alternate to change a speed at which magneticassembly moves.
 20. The non-transitory computer-readable memory mediumof claim 11, wherein the instructions, when executed, further cause thefirst current in the first electromagnetic coil and the second currentin the second electromagnetic to alternate to change a distance whichmagnetic assembly moves.